Merge #19224: [0.20] Backports

2b79ac740622218a52e2cf3ae1755dd3a8d4847a Clean up separated ban/discourage interface (Pieter Wuille)
04773480575ac79f238ac5764247dddd0cae5051 Replace automatic bans with discouragement filter (Pieter Wuille)
e7f06f9b0e84a65812d24ff6efa4bc2d3d818590 test: remove Cirrus CI FreeBSD job (fanquake)
eb6b82a5586a0cea5b72c376ff377a7322acb588 qa: Test concurrent wallet loading (João Barbosa)
c9b49d28563487e76169c7749b309244cabc70bd wallet: Handle concurrent wallet loading (João Barbosa)
cf0b5a933da540416b530ca6eb0259ab18cc6548 tests: Check that segwit inputs in psbt have both UTXO types (Andrew Chow)
3228b59b1761a80bca6aa7309cb46db5acafc905 psbt: always put a non_witness_utxo and don't remove it (Andrew Chow)
ed5ec3080419445c0af7410c0af7a421704841a6 psbt: Allow both non_witness_utxo and witness_utxo (Andrew Chow)
68e0e6f85247c8b9e0b0f039bc31c434632c2982 rpc: show both UTXOs in decodepsbt (Andrew Chow)
27786d072dbcf65cba9110f1dd171f94b6abc107 trivial: Suggested cleanups to surrounding code (Russell Yanofsky)
654420d6dfb455ca4030055881db4e3aa9ec6e8b wallet: Minimal fix to restore conflicted transaction notifications (Russell Yanofsky)
febebc4ea68104bba9ad2cf4468fc50e6136f803 Fix WSL file locking by using flock instead of fcntl (Samuel Dobson)
5c7151a60468bf3c603ffe0490fbbe95736fdd69 gui: update Qt base translations for macOS release (fanquake)
c219d21634b3eff537471c4d52e631679965d8d8 build: improved output of configure for build OS (sachinkm77)
0596a6eeb5ddb84c7095aed71bb7e6645c275f07 util: Don't reference errno when pthread fails. (MIZUTA Takeshi)

Pull request description:

  Currently backports the following to the 0.20 branch:
  * #18700 - Fix locking on WSL using flock instead of fcntl
  * #18982 - wallet: Minimal fix to restore conflicted transaction notifications
  * #19059 - gui: update Qt base translations for macOS release
  * #19152 - build: improve build OS configure output
  * #19194 -  util: Don't reference errno when pthread fails.
  * #19215 - psbt: Include and allow both non_witness_utxo and witness_utxo for segwit inputs
  * #19219 - Replace automatic bans with discouragement filter
  * #19300 - wallet: Handle concurrent wallet loading

ACKs for top commit:
  amitiuttarwar:
    ACK 04773480575ac79f238ac5764247dddd0cae5051 2b79ac740622218a52e2cf3ae1755dd3a8d4847a by comparing to original changes, double checking the diff
  sipa:
    utACK 2b79ac740622218a52e2cf3ae1755dd3a8d4847a
  laanwj:
    ACK 2b79ac740622218a52e2cf3ae1755dd3a8d4847a

Tree-SHA512: e5eb31d08288fa4a6e8aba08e60b16ce1988f14f249238b1cfd18ab2c8f6fcd9f07e3c0c491d32d2361fca26e3037fb0374f37464bddcabecea29069d6737539

39 files changed, 329 insertions, 285 deletions

diff --git a/.cirrus.yml b/.cirrus.yml
index f9c3d844be..f680715f2f 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -1,34 +1,4 @@
 task:
-  name: "FreeBsd 12.0 amd64  [GOAL: install]  [no depends, only system libs]"
-  freebsd_instance:
-    image: freebsd-12-0-release-amd64
-    cpu: 8
-    memory: 8G
-  timeout_in: 60m
-  env:
-    MAKEJOBS: "-j9"
-    CONFIGURE_OPTS: "--disable-dependency-tracking"
-    GOAL: "install"
-    TEST_RUNNER_PORT_MIN: "14000"  # Must be larger than 12321, which is used for the http cache. See https://cirrus-ci.org/guide/writing-tasks/#http-cache
-    CCACHE_SIZE: "200M"
-    CCACHE_COMPRESS: 1
-    CCACHE_DIR: "/tmp/ccache_dir"
-  ccache_cache:
-    folder: "/tmp/ccache_dir"
-  install_script:
-    - pkg install -y autoconf automake boost-libs git gmake libevent libtool pkgconf python3 ccache
-    - ./contrib/install_db4.sh $(pwd)
-    - ccache --max-size=${CCACHE_SIZE}
-  configure_script:
-    - ./autogen.sh
-    - ./configure ${CONFIGURE_OPTS} BDB_LIBS="-L$(pwd)/db4/lib -ldb_cxx-4.8" BDB_CFLAGS="-I$(pwd)/db4/include" || ( cat config.log && false)
-  make_script:
-    - gmake ${MAKEJOBS} ${GOAL} || ( echo "Build failure. Verbose build follows." && gmake ${GOAL} V=1 ; false )
-  check_script:
-    - gmake check ${MAKEJOBS} VERBOSE=1
-  functional_test_script:
-    - ./test/functional/test_runner.py --jobs 9 --ci --extended --exclude feature_dbcrash --combinedlogslen=1000 --quiet --failfast
-task:
   name: "x86_64 Linux  [GOAL: install]  [bionic]  [Using ./ci/ system]"
   container:
     image: ubuntu:18.04
diff --git a/Makefile.am b/Makefile.am
index c35f5080aa..70d4f1253a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,7 +41,7 @@ OSX_DEPLOY_SCRIPT=$(top_srcdir)/contrib/macdeploy/macdeployqtplus
 OSX_FANCY_PLIST=$(top_srcdir)/contrib/macdeploy/fancy.plist
 OSX_INSTALLER_ICONS=$(top_srcdir)/src/qt/res/icons/bitcoin.icns
 OSX_PLIST=$(top_builddir)/share/qt/Info.plist #not installed
-OSX_QT_TRANSLATIONS = da,de,es,hu,ru,uk,zh_CN,zh_TW
+OSX_QT_TRANSLATIONS = ar,bg,ca,cs,da,de,es,fa,fi,fr,gd,gl,he,hu,it,ja,ko,lt,lv,pl,pt,ru,sk,sl,sv,uk,zh_CN,zh_TW
 
 DIST_CONTRIB = \
 	       $(top_srcdir)/contrib/linearize/linearize-data.py \
diff --git a/configure.ac b/configure.ac
index c48a9a02a9..e61b65f7fa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1668,7 +1668,7 @@ echo "  gprof enabled = $enable_gprof"
 echo "  werror        = $enable_werror"
 echo
 echo "  target os     = $TARGET_OS"
-echo "  build os      = $BUILD_OS"
+echo "  build os      = $build_os"
 echo
 echo "  CC            = $CC"
 echo "  CFLAGS        = $CFLAGS"
diff --git a/depends/packages/qt.mk b/depends/packages/qt.mk
index 366b1d0c42..631851855a 100644
--- a/depends/packages/qt.mk
+++ b/depends/packages/qt.mk
@@ -10,6 +10,7 @@ $(package)_build_subdir=qtbase
 $(package)_qt_libs=corelib network widgets gui plugins testlib
 $(package)_patches=fix_qt_pkgconfig.patch mac-qmake.conf fix_configure_mac.patch fix_no_printer.patch fix_rcc_determinism.patch fix_riscv64_arch.patch xkb-default.patch no-xlib.patch fix_android_qmake_conf.patch fix_android_jni_static.patch
 
+# Update OSX_QT_TRANSLATIONS when this is updated
 $(package)_qttranslations_file_name=qttranslations-$($(package)_suffix)
 $(package)_qttranslations_sha256_hash=fb5a47799754af73d3bf501fe513342cfe2fc37f64e80df5533f6110e804220c
 
diff --git a/doc/release-notes-18982.md b/doc/release-notes-18982.md
new file mode 100644
index 0000000000..d1b8528d13
--- /dev/null
+++ b/doc/release-notes-18982.md
@@ -0,0 +1,8 @@
+Notification changes
+--------------------
+
+`-walletnotify` notifications are now sent for wallet transactions that are
+removed from the mempool because they conflict with a new block. These
+notifications were sent previously before the v0.19 release, but had been
+broken since that release (bug
+[#18325](https://github.com/bitcoin/bitcoin/issues/18325)).
diff --git a/doc/release-notes-19219.md b/doc/release-notes-19219.md
new file mode 100644
index 0000000000..b5ee885ddc
--- /dev/null
+++ b/doc/release-notes-19219.md
@@ -0,0 +1,23 @@
+#### Changes regarding misbehaving peers
+
+Peers that misbehave (e.g. send us invalid blocks) are now referred to as
+discouraged nodes in log output, as they're not (and weren't) strictly banned:
+incoming connections are still allowed from them, but they're preferred for
+eviction.
+
+Furthermore, a few additional changes are introduced to how discouraged
+addresses are treated:
+
+- Discouraging an address does not time out automatically after 24 hours
+  (or the `-bantime` setting). Depending on traffic from other peers,
+  discouragement may time out at an indeterminate time.
+
+- Discouragement is not persisted over restarts.
+
+- There is no method to list discouraged addresses. They are not returned by
+  the `listbanned` RPC. That RPC also no longer reports the `ban_reason`
+  field, as `"manually added"` is the only remaining option.
+
+- Discouragement cannot be removed with the `setban remove` RPC command.
+  If you need to remove a discouragement, you can remove all discouragements by
+  stop-starting your node.
diff --git a/src/addrdb.h b/src/addrdb.h
index c6d4307d69..8410c3776c 100644
--- a/src/addrdb.h
+++ b/src/addrdb.h
@@ -17,13 +17,6 @@ class CSubNet;
 class CAddrMan;
 class CDataStream;
 
-typedef enum BanReason
-{
-    BanReasonUnknown          = 0,
-    BanReasonNodeMisbehaving  = 1,
-    BanReasonManuallyAdded    = 2
-} BanReason;
-
 class CBanEntry
 {
 public:
@@ -31,7 +24,6 @@ public:
     int nVersion;
     int64_t nCreateTime;
     int64_t nBanUntil;
-    uint8_t banReason;
 
     CBanEntry()
     {
@@ -44,31 +36,17 @@ public:
         nCreateTime = nCreateTimeIn;
     }
 
-    explicit CBanEntry(int64_t n_create_time_in, BanReason ban_reason_in) : CBanEntry(n_create_time_in)
+    SERIALIZE_METHODS(CBanEntry, obj)
     {
-        banReason = ban_reason_in;
+        uint8_t ban_reason = 2; //! For backward compatibility
+        READWRITE(obj.nVersion, obj.nCreateTime, obj.nBanUntil, ban_reason);
     }
 
-    SERIALIZE_METHODS(CBanEntry, obj) { READWRITE(obj.nVersion, obj.nCreateTime, obj.nBanUntil, obj.banReason); }
-
     void SetNull()
     {
         nVersion = CBanEntry::CURRENT_VERSION;
         nCreateTime = 0;
         nBanUntil = 0;
-        banReason = BanReasonUnknown;
-    }
-
-    std::string banReasonToString() const
-    {
-        switch (banReason) {
-        case BanReasonNodeMisbehaving:
-            return "node misbehaving";
-        case BanReasonManuallyAdded:
-            return "manually added";
-        default:
-            return "unknown";
-        }
     }
 };
 
diff --git a/src/banman.cpp b/src/banman.cpp
index 9cc584f0e4..a1bb5be903 100644
--- a/src/banman.cpp
+++ b/src/banman.cpp
@@ -68,28 +68,13 @@ void BanMan::ClearBanned()
     if (m_client_interface) m_client_interface->BannedListChanged();
 }
 
-int BanMan::IsBannedLevel(CNetAddr net_addr)
+bool BanMan::IsDiscouraged(const CNetAddr& net_addr)
 {
-    // Returns the most severe level of banning that applies to this address.
-    // 0 - Not banned
-    // 1 - Automatic misbehavior ban
-    // 2 - Any other ban
-    int level = 0;
-    auto current_time = GetTime();
     LOCK(m_cs_banned);
-    for (const auto& it : m_banned) {
-        CSubNet sub_net = it.first;
-        CBanEntry ban_entry = it.second;
-
-        if (current_time < ban_entry.nBanUntil && sub_net.Match(net_addr)) {
-            if (ban_entry.banReason != BanReasonNodeMisbehaving) return 2;
-            level = 1;
-        }
-    }
-    return level;
+    return m_discouraged.contains(net_addr.GetAddrBytes());
 }
 
-bool BanMan::IsBanned(CNetAddr net_addr)
+bool BanMan::IsBanned(const CNetAddr& net_addr)
 {
     auto current_time = GetTime();
     LOCK(m_cs_banned);
@@ -104,7 +89,7 @@ bool BanMan::IsBanned(CNetAddr net_addr)
     return false;
 }
 
-bool BanMan::IsBanned(CSubNet sub_net)
+bool BanMan::IsBanned(const CSubNet& sub_net)
 {
     auto current_time = GetTime();
     LOCK(m_cs_banned);
@@ -118,15 +103,21 @@ bool BanMan::IsBanned(CSubNet sub_net)
     return false;
 }
 
-void BanMan::Ban(const CNetAddr& net_addr, const BanReason& ban_reason, int64_t ban_time_offset, bool since_unix_epoch)
+void BanMan::Ban(const CNetAddr& net_addr, int64_t ban_time_offset, bool since_unix_epoch)
 {
     CSubNet sub_net(net_addr);
-    Ban(sub_net, ban_reason, ban_time_offset, since_unix_epoch);
+    Ban(sub_net, ban_time_offset, since_unix_epoch);
+}
+
+void BanMan::Discourage(const CNetAddr& net_addr)
+{
+    LOCK(m_cs_banned);
+    m_discouraged.insert(net_addr.GetAddrBytes());
 }
 
-void BanMan::Ban(const CSubNet& sub_net, const BanReason& ban_reason, int64_t ban_time_offset, bool since_unix_epoch)
+void BanMan::Ban(const CSubNet& sub_net, int64_t ban_time_offset, bool since_unix_epoch)
 {
-    CBanEntry ban_entry(GetTime(), ban_reason);
+    CBanEntry ban_entry(GetTime());
 
     int64_t normalized_ban_time_offset = ban_time_offset;
     bool normalized_since_unix_epoch = since_unix_epoch;
@@ -146,8 +137,8 @@ void BanMan::Ban(const CSubNet& sub_net, const BanReason& ban_reason, int64_t ba
     }
     if (m_client_interface) m_client_interface->BannedListChanged();
 
-    //store banlist to disk immediately if user requested ban
-    if (ban_reason == BanReasonManuallyAdded) DumpBanlist();
+    //store banlist to disk immediately
+    DumpBanlist();
 }
 
 bool BanMan::Unban(const CNetAddr& net_addr)
diff --git a/src/banman.h b/src/banman.h
index 6bea2e75e9..f6bfbd1e49 100644
--- a/src/banman.h
+++ b/src/banman.h
@@ -6,6 +6,7 @@
 #define BITCOIN_BANMAN_H
 
 #include <addrdb.h>
+#include <bloom.h>
 #include <fs.h>
 #include <net_types.h> // For banmap_t
 #include <sync.h>
@@ -23,32 +24,55 @@ class CClientUIInterface;
 class CNetAddr;
 class CSubNet;
 
-// Denial-of-service detection/prevention
-// The idea is to detect peers that are behaving
-// badly and disconnect/ban them, but do it in a
-// one-coding-mistake-won't-shatter-the-entire-network
-// way.
-// IMPORTANT:  There should be nothing I can give a
-// node that it will forward on that will make that
-// node's peers drop it. If there is, an attacker
-// can isolate a node and/or try to split the network.
-// Dropping a node for sending stuff that is invalid
-// now but might be valid in a later version is also
-// dangerous, because it can cause a network split
-// between nodes running old code and nodes running
-// new code.
+// Banman manages two related but distinct concepts:
+//
+// 1. Banning. This is configured manually by the user, through the setban RPC.
+// If an address or subnet is banned, we never accept incoming connections from
+// it and never create outgoing connections to it. We won't gossip its address
+// to other peers in addr messages. Banned addresses and subnets are stored to
+// banlist.dat on shutdown and reloaded on startup. Banning can be used to
+// prevent connections with spy nodes or other griefers.
+//
+// 2. Discouragement. If a peer misbehaves enough (see Misbehaving() in
+// net_processing.cpp), we'll mark that address as discouraged. We still allow
+// incoming connections from them, but they're preferred for eviction when
+// we receive new incoming connections. We never make outgoing connections to
+// them, and do not gossip their address to other peers. This is implemented as
+// a bloom filter. We can (probabilistically) test for membership, but can't
+// list all discouraged addresses or unmark them as discouraged. Discouragement
+// can prevent our limited connection slots being used up by incompatible
+// or broken peers.
+//
+// Neither banning nor discouragement are protections against denial-of-service
+// attacks, since if an attacker has a way to waste our resources and we
+// disconnect from them and ban that address, it's trivial for them to
+// reconnect from another IP address.
+//
+// Attempting to automatically disconnect or ban any class of peer carries the
+// risk of splitting the network. For example, if we banned/disconnected for a
+// transaction that fails a policy check and a future version changes the
+// policy check so the transaction is accepted, then that transaction could
+// cause the network to split between old nodes and new nodes.
 
 class BanMan
 {
 public:
     ~BanMan();
     BanMan(fs::path ban_file, CClientUIInterface* client_interface, int64_t default_ban_time);
-    void Ban(const CNetAddr& net_addr, const BanReason& ban_reason, int64_t ban_time_offset = 0, bool since_unix_epoch = false);
-    void Ban(const CSubNet& sub_net, const BanReason& ban_reason, int64_t ban_time_offset = 0, bool since_unix_epoch = false);
+    void Ban(const CNetAddr& net_addr, int64_t ban_time_offset = 0, bool since_unix_epoch = false);
+    void Ban(const CSubNet& sub_net, int64_t ban_time_offset = 0, bool since_unix_epoch = false);
+    void Discourage(const CNetAddr& net_addr);
     void ClearBanned();
-    int IsBannedLevel(CNetAddr net_addr);
-    bool IsBanned(CNetAddr net_addr);
-    bool IsBanned(CSubNet sub_net);
+
+    //! Return whether net_addr is banned
+    bool IsBanned(const CNetAddr& net_addr);
+
+    //! Return whether sub_net is exactly banned
+    bool IsBanned(const CSubNet& sub_net);
+
+    //! Return whether net_addr is discouraged.
+    bool IsDiscouraged(const CNetAddr& net_addr);
+
     bool Unban(const CNetAddr& net_addr);
     bool Unban(const CSubNet& sub_net);
     void GetBanned(banmap_t& banmap);
@@ -68,6 +92,7 @@ private:
     CClientUIInterface* m_client_interface = nullptr;
     CBanDB m_ban_db;
     const int64_t m_default_ban_time;
+    CRollingBloomFilter m_discouraged GUARDED_BY(m_cs_banned) {50000, 0.000001};
 };
 
 #endif
diff --git a/src/fs.cpp b/src/fs.cpp
index 066c6c10d3..e68c97b3ca 100644
--- a/src/fs.cpp
+++ b/src/fs.cpp
@@ -6,6 +6,9 @@
 
 #ifndef WIN32
 #include <fcntl.h>
+#include <string>
+#include <sys/file.h>
+#include <sys/utsname.h>
 #else
 #ifndef NOMINMAX
 #define NOMINMAX
@@ -47,20 +50,38 @@ FileLock::~FileLock()
     }
 }
 
+static bool IsWSL()
+{
+    struct utsname uname_data;
+    return uname(&uname_data) == 0 && std::string(uname_data.version).find("Microsoft") != std::string::npos;
+}
+
 bool FileLock::TryLock()
 {
     if (fd == -1) {
         return false;
     }
-    struct flock lock;
-    lock.l_type = F_WRLCK;
-    lock.l_whence = SEEK_SET;
-    lock.l_start = 0;
-    lock.l_len = 0;
-    if (fcntl(fd, F_SETLK, &lock) == -1) {
-        reason = GetErrorReason();
-        return false;
+
+    // Exclusive file locking is broken on WSL using fcntl (issue #18622)
+    // This workaround can be removed once the bug on WSL is fixed
+    static const bool is_wsl = IsWSL();
+    if (is_wsl) {
+        if (flock(fd, LOCK_EX | LOCK_NB) == -1) {
+            reason = GetErrorReason();
+            return false;
+        }
+    } else {
+        struct flock lock;
+        lock.l_type = F_WRLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = 0;
+        lock.l_len = 0;
+        if (fcntl(fd, F_SETLK, &lock) == -1) {
+            reason = GetErrorReason();
+            return false;
+        }
     }
+
     return true;
 }
 #else
diff --git a/src/init.cpp b/src/init.cpp
index d015fb4b6b..f381a53b1b 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -422,8 +422,8 @@ void SetupServerArgs()
 
     gArgs.AddArg("-addnode=<ip>", "Add a node to connect to and attempt to keep the connection open (see the `addnode` RPC command help for more info). This option can be specified multiple times to add multiple nodes.", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-asmap=<file>", strprintf("Specify asn mapping used for bucketing of the peers (default: %s). Relative paths will be prefixed by the net-specific datadir location.", DEFAULT_ASMAP_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    gArgs.AddArg("-banscore=<n>", strprintf("Threshold for disconnecting misbehaving peers (default: %u)", DEFAULT_BANSCORE_THRESHOLD), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    gArgs.AddArg("-bantime=<n>", strprintf("Number of seconds to keep misbehaving peers from reconnecting (default: %u)", DEFAULT_MISBEHAVING_BANTIME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    gArgs.AddArg("-banscore=<n>", strprintf("Threshold for disconnecting and discouraging misbehaving peers (default: %u)", DEFAULT_BANSCORE_THRESHOLD), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    gArgs.AddArg("-bantime=<n>", strprintf("Default duration (in seconds) of manually configured bans (default: %u)", DEFAULT_MISBEHAVING_BANTIME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-bind=<addr>", "Bind to given address and always listen on it. Use [host]:port notation for IPv6", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-connect=<ip>", "Connect only to the specified node; -noconnect disables automatic connections (the rules for this peer are the same as for -addnode). This option can be specified multiple times to connect to multiple nodes.", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-discover", "Discover own IP addresses (default: 1 when listening and no -externalip or -proxy)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
diff --git a/src/interfaces/chain.cpp b/src/interfaces/chain.cpp
index 0b3cd08e22..7c58273f82 100644
--- a/src/interfaces/chain.cpp
+++ b/src/interfaces/chain.cpp
@@ -158,9 +158,9 @@ public:
     {
         m_notifications->transactionAddedToMempool(tx);
     }
-    void TransactionRemovedFromMempool(const CTransactionRef& tx) override
+    void TransactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) override
     {
-        m_notifications->transactionRemovedFromMempool(tx);
+        m_notifications->transactionRemovedFromMempool(tx, reason);
     }
     void BlockConnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* index) override
     {
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index e1bc9bbbf3..538aaae23b 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -20,6 +20,7 @@ class CRPCCommand;
 class CScheduler;
 class Coin;
 class uint256;
+enum class MemPoolRemovalReason;
 enum class RBFTransactionState;
 struct CBlockLocator;
 struct FeeCalculation;
@@ -221,7 +222,7 @@ public:
     public:
         virtual ~Notifications() {}
         virtual void transactionAddedToMempool(const CTransactionRef& tx) {}
-        virtual void transactionRemovedFromMempool(const CTransactionRef& ptx) {}
+        virtual void transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {}
         virtual void blockConnected(const CBlock& block, int height) {}
         virtual void blockDisconnected(const CBlock& block, int height) {}
         virtual void updatedBlockTip() {}
diff --git a/src/interfaces/node.cpp b/src/interfaces/node.cpp
index 905173d20b..3bd32909bf 100644
--- a/src/interfaces/node.cpp
+++ b/src/interfaces/node.cpp
@@ -136,10 +136,10 @@ public:
         }
         return false;
     }
-    bool ban(const CNetAddr& net_addr, BanReason reason, int64_t ban_time_offset) override
+    bool ban(const CNetAddr& net_addr, int64_t ban_time_offset) override
     {
         if (m_context.banman) {
-            m_context.banman->Ban(net_addr, reason, ban_time_offset);
+            m_context.banman->Ban(net_addr, ban_time_offset);
             return true;
         }
         return false;
diff --git a/src/interfaces/node.h b/src/interfaces/node.h
index 53a20886cd..61acde0523 100644
--- a/src/interfaces/node.h
+++ b/src/interfaces/node.h
@@ -118,7 +118,7 @@ public:
     virtual bool getBanned(banmap_t& banmap) = 0;
 
     //! Ban node.
-    virtual bool ban(const CNetAddr& net_addr, BanReason reason, int64_t ban_time_offset) = 0;
+    virtual bool ban(const CNetAddr& net_addr, int64_t ban_time_offset) = 0;
 
     //! Unban node.
     virtual bool unban(const CSubNet& ip) = 0;
diff --git a/src/net.cpp b/src/net.cpp
index dcc613ba88..09ddcb163d 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -996,17 +996,24 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
     // on all platforms.  Set it again here just to be sure.
     SetSocketNoDelay(hSocket);
 
-    int bannedlevel = m_banman ? m_banman->IsBannedLevel(addr) : 0;
-
-    // Don't accept connections from banned peers, but if our inbound slots aren't almost full, accept
-    // if the only banning reason was an automatic misbehavior ban.
-    if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && bannedlevel > ((nInbound + 1 < nMaxInbound) ? 1 : 0))
+    // Don't accept connections from banned peers.
+    bool banned = m_banman->IsBanned(addr);
+    if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && banned)
     {
         LogPrint(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToString());
         CloseSocket(hSocket);
         return;
     }
 
+    // Only accept connections from discouraged peers if our inbound slots aren't (almost) full.
+    bool discouraged = m_banman->IsDiscouraged(addr);
+    if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && nInbound + 1 >= nMaxInbound && discouraged)
+    {
+        LogPrint(BCLog::NET, "connection from %s dropped (discouraged)\n", addr.ToString());
+        CloseSocket(hSocket);
+        return;
+    }
+
     if (nInbound >= nMaxInbound)
     {
         if (!AttemptToEvictConnection()) {
@@ -1030,7 +1037,7 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
     pnode->m_permissionFlags = permissionFlags;
     // If this flag is present, the user probably expect that RPC and QT report it as whitelisted (backward compatibility)
     pnode->m_legacyWhitelisted = legacyWhitelisted;
-    pnode->m_prefer_evict = bannedlevel > 0;
+    pnode->m_prefer_evict = discouraged;
     m_msgproc->InitializeNode(pnode);
 
     LogPrint(BCLog::NET, "connection from %s accepted\n", addr.ToString());
@@ -1987,10 +1994,10 @@ void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFai
         return;
     }
     if (!pszDest) {
-        if (IsLocal(addrConnect) ||
-            FindNode(static_cast<CNetAddr>(addrConnect)) || (m_banman && m_banman->IsBanned(addrConnect)) ||
-            FindNode(addrConnect.ToStringIPPort()))
+        bool banned_or_discouraged = m_banman && (m_banman->IsDiscouraged(addrConnect) || m_banman->IsBanned(addrConnect));
+        if (IsLocal(addrConnect) || FindNode(static_cast<CNetAddr>(addrConnect)) || banned_or_discouraged || FindNode(addrConnect.ToStringIPPort())) {
             return;
+        }
     } else if (FindNode(std::string(pszDest)))
         return;
 
diff --git a/src/net_permissions.h b/src/net_permissions.h
index ad74848347..a1b45c4009 100644
--- a/src/net_permissions.h
+++ b/src/net_permissions.h
@@ -18,7 +18,7 @@ enum NetPermissionFlags
     // Always relay transactions from this peer, even if already in mempool
     // Keep parameter interaction: forcerelay implies relay
     PF_FORCERELAY = (1U << 2) | PF_RELAY,
-    // Can't be banned for misbehavior
+    // Can't be banned/disconnected/discouraged for misbehavior
     PF_NOBAN = (1U << 4),
     // Can query the mempool
     PF_MEMPOOL = (1U << 5),
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 2a61f84a08..ddc516ce0f 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -215,8 +215,8 @@ struct CNodeState {
     bool fCurrentlyConnected;
     //! Accumulated misbehaviour score for this peer.
     int nMisbehavior;
-    //! Whether this peer should be disconnected and banned (unless whitelisted).
-    bool fShouldBan;
+    //! Whether this peer should be disconnected and marked as discouraged (unless whitelisted with noban).
+    bool m_should_discourage;
     //! String name of this peer (debugging/logging purposes).
     const std::string name;
     //! The best known block we know this peer has announced.
@@ -367,7 +367,7 @@ struct CNodeState {
     {
         fCurrentlyConnected = false;
         nMisbehavior = 0;
-        fShouldBan = false;
+        m_should_discourage = false;
         pindexBestKnownBlock = nullptr;
         hashLastUnknownBlock.SetNull();
         pindexLastCommonBlock = nullptr;
@@ -963,7 +963,7 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
 }
 
 /**
- * Mark a misbehaving peer to be banned depending upon the value of `-banscore`.
+ * Increment peer's misbehavior score. If the new value surpasses banscore (specified on startup or by default), mark node to be discouraged, meaning the peer might be disconnected & added to the discouragement filter.
  */
 void Misbehaving(NodeId pnode, int howmuch, const std::string& message) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
@@ -979,14 +979,14 @@ void Misbehaving(NodeId pnode, int howmuch, const std::string& message) EXCLUSIV
     std::string message_prefixed = message.empty() ? "" : (": " + message);
     if (state->nMisbehavior >= banscore && state->nMisbehavior - howmuch < banscore)
     {
-        LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d) BAN THRESHOLD EXCEEDED%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed);
-        state->fShouldBan = true;
+        LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d) DISCOURAGE THRESHOLD EXCEEDED%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed);
+        state->m_should_discourage = true;
     } else
         LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d)%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed);
 }
 
 /**
- * Potentially ban a node based on the contents of a BlockValidationState object
+ * Potentially mark a node discouraged based on the contents of a BlockValidationState object
  *
  * @param[in] via_compact_block this bool is passed in because net_processing should
  * punish peers differently depending on whether the data was provided in a compact
@@ -1016,7 +1016,7 @@ static bool MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& s
                 break;
             }
 
-            // Ban outbound (but not inbound) peers if on an invalid chain.
+            // Discourage outbound (but not inbound) peers if on an invalid chain.
             // Exempt HB compact block peers and manual connections.
             if (!via_compact_block && !node_state->m_is_inbound && !node_state->m_is_manual_connection) {
                 Misbehaving(nodeid, 100, message);
@@ -1051,7 +1051,7 @@ static bool MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& s
 }
 
 /**
- * Potentially ban a node based on the contents of a TxValidationState object
+ * Potentially disconnect and discourage a node based on the contents of a TxValidationState object
  *
  * @return Returns true if the peer was punished (probably disconnected)
  */
@@ -1278,7 +1278,7 @@ void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CB
 }
 
 /**
- * Handle invalid block rejection and consequent peer banning, maintain which
+ * Handle invalid block rejection and consequent peer discouragement, maintain which
  * peers announce compact blocks.
  */
 void PeerLogicValidation::BlockChecked(const CBlock& block, const BlockValidationState& state) {
@@ -2191,7 +2191,8 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
                 addr.nTime = nNow - 5 * 24 * 60 * 60;
             pfrom->AddAddressKnown(addr);
-            if (banman->IsBanned(addr)) continue; // Do not process banned addresses beyond remembering we received them
+            if (banman->IsDiscouraged(addr)) continue; // Do not process banned/discouraged addresses beyond remembering we received them
+            if (banman->IsBanned(addr)) continue;
             bool fReachable = IsReachable(addr);
             if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable())
             {
@@ -2833,7 +2834,7 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
             // relayed before full validation (see BIP 152), so we don't want to disconnect
             // the peer if the header turns out to be for an invalid block.
             // Note that if a peer tries to build on an invalid chain, that
-            // will be detected and the peer will be banned.
+            // will be detected and the peer will be disconnected/discouraged.
             return ProcessHeadersMessage(pfrom, connman, mempool, {cmpctblock.header}, chainparams, /*via_compact_block=*/true);
         }
 
@@ -2919,7 +2920,7 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
                 // 3. the block is otherwise invalid (eg invalid coinbase,
                 //    block is too big, too many legacy sigops, etc).
                 // So if CheckBlock failed, #3 is the only possibility.
-                // Under BIP 152, we don't DoS-ban unless proof of work is
+                // Under BIP 152, we don't discourage the peer unless proof of work is
                 // invalid (we don't require all the stateless checks to have
                 // been run).  This is handled below, so just treat this as
                 // though the block was successfully read, and rely on the
@@ -3044,7 +3045,7 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
         std::vector<CAddress> vAddr = connman->GetAddresses();
         FastRandomContext insecure_rand;
         for (const CAddress &addr : vAddr) {
-            if (!banman->IsBanned(addr)) {
+            if (!banman->IsDiscouraged(addr) && !banman->IsBanned(addr)) {
                 pfrom->PushAddress(addr, insecure_rand);
             }
         }
@@ -3255,25 +3256,26 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
     return true;
 }
 
-bool PeerLogicValidation::CheckIfBanned(CNode* pnode)
+bool PeerLogicValidation::MaybeDiscourageAndDisconnect(CNode* pnode)
 {
     AssertLockHeld(cs_main);
     CNodeState &state = *State(pnode->GetId());
 
-    if (state.fShouldBan) {
-        state.fShouldBan = false;
-        if (pnode->HasPermission(PF_NOBAN))
+    if (state.m_should_discourage) {
+        state.m_should_discourage = false;
+        if (pnode->HasPermission(PF_NOBAN)) {
             LogPrintf("Warning: not punishing whitelisted peer %s!\n", pnode->addr.ToString());
-        else if (pnode->m_manual_connection)
+        } else if (pnode->m_manual_connection) {
             LogPrintf("Warning: not punishing manually-connected peer %s!\n", pnode->addr.ToString());
-        else if (pnode->addr.IsLocal()) {
-            // Disconnect but don't ban _this_ local node
-            LogPrintf("Warning: disconnecting but not banning local peer %s!\n", pnode->addr.ToString());
+        } else if (pnode->addr.IsLocal()) {
+            // Disconnect but don't discourage this local node
+            LogPrintf("Warning: disconnecting but not discouraging local peer %s!\n", pnode->addr.ToString());
             pnode->fDisconnect = true;
         } else {
-            // Disconnect and ban all nodes sharing the address
+            // Disconnect and discourage all nodes sharing the address
+            LogPrintf("Disconnecting and discouraging peer %s!\n", pnode->addr.ToString());
             if (m_banman) {
-                m_banman->Ban(pnode->addr, BanReasonNodeMisbehaving);
+                m_banman->Discourage(pnode->addr);
             }
             connman->DisconnectNode(pnode->addr);
         }
@@ -3380,7 +3382,7 @@ bool PeerLogicValidation::ProcessMessages(CNode* pfrom, std::atomic<bool>& inter
     }
 
     LOCK(cs_main);
-    CheckIfBanned(pfrom);
+    MaybeDiscourageAndDisconnect(pfrom);
 
     return fMoreWork;
 }
@@ -3583,7 +3585,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto)
         if (!lockMain)
             return true;
 
-        if (CheckIfBanned(pto)) return true;
+        if (MaybeDiscourageAndDisconnect(pto)) return true;
 
         CNodeState &state = *State(pto->GetId());
 
diff --git a/src/net_processing.h b/src/net_processing.h
index 3d9bc65a3a..ddb1780148 100644
--- a/src/net_processing.h
+++ b/src/net_processing.h
@@ -28,7 +28,7 @@ private:
     BanMan* const m_banman;
     CTxMemPool& m_mempool;
 
-    bool CheckIfBanned(CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
+    bool MaybeDiscourageAndDisconnect(CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 public:
     PeerLogicValidation(CConnman* connman, BanMan* banman, CScheduler& scheduler, CTxMemPool& pool);
diff --git a/src/netaddress.h b/src/netaddress.h
index b7381c1eb4..0c8d600a4a 100644
--- a/src/netaddress.h
+++ b/src/netaddress.h
@@ -90,6 +90,7 @@ class CNetAddr
         uint32_t GetMappedAS(const std::vector<bool> &asmap) const;
 
         std::vector<unsigned char> GetGroup(const std::vector<bool> &asmap) const;
+        std::vector<unsigned char> GetAddrBytes() const { return {std::begin(ip), std::end(ip)}; }
         int GetReachabilityFrom(const CNetAddr *paddrPartner = nullptr) const;
 
         explicit CNetAddr(const struct in6_addr& pipv6Addr, const uint32_t scope = 0);
diff --git a/src/psbt.cpp b/src/psbt.cpp
index e6b6285652..bfa9e3c667 100644
--- a/src/psbt.cpp
+++ b/src/psbt.cpp
@@ -35,14 +35,6 @@ bool PartiallySignedTransaction::Merge(const PartiallySignedTransaction& psbt)
     return true;
 }
 
-bool PartiallySignedTransaction::IsSane() const
-{
-    for (PSBTInput input : inputs) {
-        if (!input.IsSane()) return false;
-    }
-    return true;
-}
-
 bool PartiallySignedTransaction::AddInput(const CTxIn& txin, PSBTInput& psbtin)
 {
     if (std::find(tx->vin.begin(), tx->vin.end(), txin) != tx->vin.end()) {
@@ -144,8 +136,8 @@ void PSBTInput::Merge(const PSBTInput& input)
 {
     if (!non_witness_utxo && input.non_witness_utxo) non_witness_utxo = input.non_witness_utxo;
     if (witness_utxo.IsNull() && !input.witness_utxo.IsNull()) {
+        // TODO: For segwit v1, we will want to clear out the non-witness utxo when setting a witness one. For v0 and non-segwit, this is not safe
         witness_utxo = input.witness_utxo;
-        non_witness_utxo = nullptr; // Clear out any non-witness utxo when we set a witness one.
     }
 
     partial_sigs.insert(input.partial_sigs.begin(), input.partial_sigs.end());
@@ -158,18 +150,6 @@ void PSBTInput::Merge(const PSBTInput& input)
     if (final_script_witness.IsNull() && !input.final_script_witness.IsNull()) final_script_witness = input.final_script_witness;
 }
 
-bool PSBTInput::IsSane() const
-{
-    // Cannot have both witness and non-witness utxos
-    if (!witness_utxo.IsNull() && non_witness_utxo) return false;
-
-    // If we have a witness_script or a scriptWitness, we must also have a witness utxo
-    if (!witness_script.empty() && witness_utxo.IsNull()) return false;
-    if (!final_script_witness.IsNull() && witness_utxo.IsNull()) return false;
-
-    return true;
-}
-
 void PSBTOutput::FillSignatureData(SignatureData& sigdata) const
 {
     if (!redeem_script.empty()) {
@@ -250,11 +230,6 @@ bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction&
     bool require_witness_sig = false;
     CTxOut utxo;
 
-    // Verify input sanity, which checks that at most one of witness or non-witness utxos is provided.
-    if (!input.IsSane()) {
-        return false;
-    }
-
     if (input.non_witness_utxo) {
         // If we're taking our information from a non-witness UTXO, verify that it matches the prevout.
         COutPoint prevout = tx.vin[index].prevout;
@@ -288,10 +263,11 @@ bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction&
     if (require_witness_sig && !sigdata.witness) return false;
     input.FromSignatureData(sigdata);
 
-    // If we have a witness signature, use the smaller witness UTXO.
+    // If we have a witness signature, put a witness UTXO.
+    // TODO: For segwit v1, we should remove the non_witness_utxo
     if (sigdata.witness) {
         input.witness_utxo = utxo;
-        input.non_witness_utxo = nullptr;
+        // input.non_witness_utxo = nullptr;
     }
 
     // Fill in the missing info
@@ -345,10 +321,6 @@ TransactionError CombinePSBTs(PartiallySignedTransaction& out, const std::vector
             return TransactionError::PSBT_MISMATCH;
         }
     }
-    if (!out.IsSane()) {
-        return TransactionError::INVALID_PSBT;
-    }
-
     return TransactionError::OK;
 }
 
diff --git a/src/psbt.h b/src/psbt.h
index dfba261961..6eb411e3a4 100644
--- a/src/psbt.h
+++ b/src/psbt.h
@@ -58,18 +58,17 @@ struct PSBTInput
     void FillSignatureData(SignatureData& sigdata) const;
     void FromSignatureData(const SignatureData& sigdata);
     void Merge(const PSBTInput& input);
-    bool IsSane() const;
     PSBTInput() {}
 
     template <typename Stream>
     inline void Serialize(Stream& s) const {
         // Write the utxo
-        // If there is a non-witness utxo, then don't add the witness one.
         if (non_witness_utxo) {
             SerializeToVector(s, PSBT_IN_NON_WITNESS_UTXO);
             OverrideStream<Stream> os(&s, s.GetType(), s.GetVersion() | SERIALIZE_TRANSACTION_NO_WITNESS);
             SerializeToVector(os, non_witness_utxo);
-        } else if (!witness_utxo.IsNull()) {
+        }
+        if (!witness_utxo.IsNull()) {
             SerializeToVector(s, PSBT_IN_WITNESS_UTXO);
             SerializeToVector(s, witness_utxo);
         }
@@ -280,7 +279,6 @@ struct PSBTOutput
     void FillSignatureData(SignatureData& sigdata) const;
     void FromSignatureData(const SignatureData& sigdata);
     void Merge(const PSBTOutput& output);
-    bool IsSane() const;
     PSBTOutput() {}
 
     template <typename Stream>
@@ -397,7 +395,6 @@ struct PartiallySignedTransaction
     /** Merge psbt into this. The two psbts must have the same underlying CTransaction (i.e. the
       * same actual Bitcoin transaction.) Returns true if the merge succeeded, false otherwise. */
     NODISCARD bool Merge(const PartiallySignedTransaction& psbt);
-    bool IsSane() const;
     bool AddInput(const CTxIn& txin, PSBTInput& psbtin);
     bool AddOutput(const CTxOut& txout, const PSBTOutput& psbtout);
     PartiallySignedTransaction() {}
@@ -547,10 +544,6 @@ struct PartiallySignedTransaction
         if (outputs.size() != tx->vout.size()) {
             throw std::ios_base::failure("Outputs provided does not match the number of outputs in transaction.");
         }
-        // Sanity check
-        if (!IsSane()) {
-            throw std::ios_base::failure("PSBT is not sane.");
-        }
     }
 
     template <typename Stream>
diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
index 0ffdc892c5..01e387f74b 100644
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -1216,7 +1216,7 @@ void RPCConsole::banSelectedNode(int bantime)
         // Find possible nodes, ban it and clear the selected node
         const CNodeCombinedStats *stats = clientModel->getPeerTableModel()->getNodeStats(detailNodeRow);
         if (stats) {
-            m_node.ban(stats->nodeStats.addr, BanReasonManuallyAdded, bantime);
+            m_node.ban(stats->nodeStats.addr, bantime);
             m_node.disconnectByAddress(stats->nodeStats.addr);
         }
     }
diff --git a/src/rpc/net.cpp b/src/rpc/net.cpp
index 10562126db..8c400c05a0 100644
--- a/src/rpc/net.cpp
+++ b/src/rpc/net.cpp
@@ -604,12 +604,12 @@ static UniValue setban(const JSONRPCRequest& request)
             absolute = true;
 
         if (isSubnet) {
-            g_rpc_node->banman->Ban(subNet, BanReasonManuallyAdded, banTime, absolute);
+            g_rpc_node->banman->Ban(subNet, banTime, absolute);
             if (g_rpc_node->connman) {
                 g_rpc_node->connman->DisconnectNode(subNet);
             }
         } else {
-            g_rpc_node->banman->Ban(netAddr, BanReasonManuallyAdded, banTime, absolute);
+            g_rpc_node->banman->Ban(netAddr, banTime, absolute);
             if (g_rpc_node->connman) {
                 g_rpc_node->connman->DisconnectNode(netAddr);
             }
@@ -618,7 +618,7 @@ static UniValue setban(const JSONRPCRequest& request)
     else if(strCommand == "remove")
     {
         if (!( isSubnet ? g_rpc_node->banman->Unban(subNet) : g_rpc_node->banman->Unban(netAddr) )) {
-            throw JSONRPCError(RPC_CLIENT_INVALID_IP_OR_SUBNET, "Error: Unban failed. Requested address/subnet was not previously banned.");
+            throw JSONRPCError(RPC_CLIENT_INVALID_IP_OR_SUBNET, "Error: Unban failed. Requested address/subnet was not previously manually banned.");
         }
     }
     return NullUniValue;
@@ -627,7 +627,7 @@ static UniValue setban(const JSONRPCRequest& request)
 static UniValue listbanned(const JSONRPCRequest& request)
 {
             RPCHelpMan{"listbanned",
-                "\nList all banned IPs/Subnets.\n",
+                "\nList all manually banned IPs/Subnets.\n",
                 {},
         RPCResult{RPCResult::Type::ARR, "", "",
             {
@@ -636,7 +636,6 @@ static UniValue listbanned(const JSONRPCRequest& request)
                         {RPCResult::Type::STR, "address", ""},
                         {RPCResult::Type::NUM_TIME, "banned_until", ""},
                         {RPCResult::Type::NUM_TIME, "ban_created", ""},
-                        {RPCResult::Type::STR, "ban_reason", ""},
                     }},
             }},
                 RPCExamples{
@@ -660,7 +659,6 @@ static UniValue listbanned(const JSONRPCRequest& request)
         rec.pushKV("address", entry.first.ToString());
         rec.pushKV("banned_until", banEntry.nBanUntil);
         rec.pushKV("ban_created", banEntry.nCreateTime);
-        rec.pushKV("ban_reason", banEntry.banReasonToString());
 
         bannedAddresses.push_back(rec);
     }
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 3c0b060439..746900fdab 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -1116,6 +1116,7 @@ UniValue decodepsbt(const JSONRPCRequest& request)
         const PSBTInput& input = psbtx.inputs[i];
         UniValue in(UniValue::VOBJ);
         // UTXOs
+        bool have_a_utxo = false;
         if (!input.witness_utxo.IsNull()) {
             const CTxOut& txout = input.witness_utxo;
 
@@ -1133,7 +1134,9 @@ UniValue decodepsbt(const JSONRPCRequest& request)
             ScriptToUniv(txout.scriptPubKey, o, true);
             out.pushKV("scriptPubKey", o);
             in.pushKV("witness_utxo", out);
-        } else if (input.non_witness_utxo) {
+            have_a_utxo = true;
+        }
+        if (input.non_witness_utxo) {
             UniValue non_wit(UniValue::VOBJ);
             TxToUniv(*input.non_witness_utxo, uint256(), non_wit, false);
             in.pushKV("non_witness_utxo", non_wit);
@@ -1144,7 +1147,9 @@ UniValue decodepsbt(const JSONRPCRequest& request)
                 // Hack to just not show fee later
                 have_all_utxos = false;
             }
-        } else {
+            have_a_utxo = true;
+        }
+        if (!have_a_utxo) {
             have_all_utxos = false;
         }
 
diff --git a/src/test/denialofservice_tests.cpp b/src/test/denialofservice_tests.cpp
index 6314c1a42f..41d10ae321 100644
--- a/src/test/denialofservice_tests.cpp
+++ b/src/test/denialofservice_tests.cpp
@@ -238,8 +238,8 @@ BOOST_AUTO_TEST_CASE(DoS_banning)
         LOCK2(cs_main, dummyNode1.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode1));
     }
-    BOOST_CHECK(banman->IsBanned(addr1));
-    BOOST_CHECK(!banman->IsBanned(ip(0xa0b0c001|0x0000ff00))); // Different IP, not banned
+    BOOST_CHECK(banman->IsDiscouraged(addr1));
+    BOOST_CHECK(!banman->IsDiscouraged(ip(0xa0b0c001|0x0000ff00))); // Different IP, not banned
 
     CAddress addr2(ip(0xa0b0c002), NODE_NONE);
     CNode dummyNode2(id++, NODE_NETWORK, 0, INVALID_SOCKET, addr2, 1, 1, CAddress(), "", true);
@@ -255,8 +255,8 @@ BOOST_AUTO_TEST_CASE(DoS_banning)
         LOCK2(cs_main, dummyNode2.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode2));
     }
-    BOOST_CHECK(!banman->IsBanned(addr2)); // 2 not banned yet...
-    BOOST_CHECK(banman->IsBanned(addr1));  // ... but 1 still should be
+    BOOST_CHECK(!banman->IsDiscouraged(addr2)); // 2 not banned yet...
+    BOOST_CHECK(banman->IsDiscouraged(addr1));  // ... but 1 still should be
     {
         LOCK(cs_main);
         Misbehaving(dummyNode2.GetId(), 50);
@@ -265,7 +265,7 @@ BOOST_AUTO_TEST_CASE(DoS_banning)
         LOCK2(cs_main, dummyNode2.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode2));
     }
-    BOOST_CHECK(banman->IsBanned(addr2));
+    BOOST_CHECK(banman->IsDiscouraged(addr2));
 
     bool dummy;
     peerLogic->FinalizeNode(dummyNode1.GetId(), dummy);
@@ -294,7 +294,7 @@ BOOST_AUTO_TEST_CASE(DoS_banscore)
         LOCK2(cs_main, dummyNode1.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode1));
     }
-    BOOST_CHECK(!banman->IsBanned(addr1));
+    BOOST_CHECK(!banman->IsDiscouraged(addr1));
     {
         LOCK(cs_main);
         Misbehaving(dummyNode1.GetId(), 10);
@@ -303,7 +303,7 @@ BOOST_AUTO_TEST_CASE(DoS_banscore)
         LOCK2(cs_main, dummyNode1.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode1));
     }
-    BOOST_CHECK(!banman->IsBanned(addr1));
+    BOOST_CHECK(!banman->IsDiscouraged(addr1));
     {
         LOCK(cs_main);
         Misbehaving(dummyNode1.GetId(), 1);
@@ -312,7 +312,7 @@ BOOST_AUTO_TEST_CASE(DoS_banscore)
         LOCK2(cs_main, dummyNode1.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode1));
     }
-    BOOST_CHECK(banman->IsBanned(addr1));
+    BOOST_CHECK(banman->IsDiscouraged(addr1));
     gArgs.ForceSetArg("-banscore", ToString(DEFAULT_BANSCORE_THRESHOLD));
 
     bool dummy;
@@ -344,13 +344,7 @@ BOOST_AUTO_TEST_CASE(DoS_bantime)
         LOCK2(cs_main, dummyNode.cs_sendProcessing);
         BOOST_CHECK(peerLogic->SendMessages(&dummyNode));
     }
-    BOOST_CHECK(banman->IsBanned(addr));
-
-    SetMockTime(nStartTime+60*60);
-    BOOST_CHECK(banman->IsBanned(addr));
-
-    SetMockTime(nStartTime+60*60*24+1);
-    BOOST_CHECK(!banman->IsBanned(addr));
+    BOOST_CHECK(banman->IsDiscouraged(addr));
 
     bool dummy;
     peerLogic->FinalizeNode(dummyNode.GetId(), dummy);
diff --git a/src/test/fuzz/addrdb.cpp b/src/test/fuzz/addrdb.cpp
index f21ff3fac3..a7e6e8961a 100644
--- a/src/test/fuzz/addrdb.cpp
+++ b/src/test/fuzz/addrdb.cpp
@@ -18,18 +18,11 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
 
     const CBanEntry ban_entry = [&] {
-        switch (fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 3)) {
+        switch (fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 2)) {
         case 0:
             return CBanEntry{fuzzed_data_provider.ConsumeIntegral<int64_t>()};
             break;
-        case 1:
-            return CBanEntry{fuzzed_data_provider.ConsumeIntegral<int64_t>(), fuzzed_data_provider.PickValueInArray<BanReason>({
-                                                                                  BanReason::BanReasonUnknown,
-                                                                                  BanReason::BanReasonNodeMisbehaving,
-                                                                                  BanReason::BanReasonManuallyAdded,
-                                                                              })};
-            break;
-        case 2: {
+        case 1: {
             const Optional<CBanEntry> ban_entry = ConsumeDeserializable<CBanEntry>(fuzzed_data_provider);
             if (ban_entry) {
                 return *ban_entry;
@@ -39,5 +32,4 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         }
         return CBanEntry{};
     }();
-    assert(!ban_entry.banReasonToString().empty());
 }
diff --git a/src/test/fuzz/psbt.cpp b/src/test/fuzz/psbt.cpp
index ca3e0b8586..fe8bd20816 100644
--- a/src/test/fuzz/psbt.cpp
+++ b/src/test/fuzz/psbt.cpp
@@ -39,7 +39,6 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     }
 
     (void)psbt.IsNull();
-    (void)psbt.IsSane();
 
     Optional<CMutableTransaction> tx = psbt.tx;
     if (tx) {
@@ -50,7 +49,6 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     for (const PSBTInput& input : psbt.inputs) {
         (void)PSBTInputSigned(input);
         (void)input.IsNull();
-        (void)input.IsSane();
     }
 
     for (const PSBTOutput& output : psbt.outputs) {
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 47b0d39ea4..c14417a847 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -410,7 +410,7 @@ void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason)
         // for any reason except being included in a block. Clients interested
         // in transactions included in blocks can subscribe to the BlockConnected
         // notification.
-        GetMainSignals().TransactionRemovedFromMempool(it->GetSharedTx());
+        GetMainSignals().TransactionRemovedFromMempool(it->GetSharedTx(), reason);
     }
 
     const uint256 hash = it->GetTx().GetHash();
diff --git a/src/util/system.cpp b/src/util/system.cpp
index b0a538b527..b6a7f3926d 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -1155,8 +1155,9 @@ void ScheduleBatchPriority()
 {
 #ifdef SCHED_BATCH
     const static sched_param param{};
-    if (pthread_setschedparam(pthread_self(), SCHED_BATCH, &param) != 0) {
-        LogPrintf("Failed to pthread_setschedparam: %s\n", strerror(errno));
+    const int rc = pthread_setschedparam(pthread_self(), SCHED_BATCH, &param);
+    if (rc != 0) {
+        LogPrintf("Failed to pthread_setschedparam: %s\n", strerror(rc));
     }
 #endif
 }
diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
index 11000774c0..6a2c151806 100644
--- a/src/validationinterface.cpp
+++ b/src/validationinterface.cpp
@@ -190,22 +190,22 @@ void CMainSignals::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockInd
                           fInitialDownload);
 }
 
-void CMainSignals::TransactionAddedToMempool(const CTransactionRef &ptx) {
-    auto event = [ptx, this] {
-        m_internals->Iterate([&](CValidationInterface& callbacks) { callbacks.TransactionAddedToMempool(ptx); });
+void CMainSignals::TransactionAddedToMempool(const CTransactionRef& tx) {
+    auto event = [tx, this] {
+        m_internals->Iterate([&](CValidationInterface& callbacks) { callbacks.TransactionAddedToMempool(tx); });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: txid=%s wtxid=%s", __func__,
-                          ptx->GetHash().ToString(),
-                          ptx->GetWitnessHash().ToString());
+                          tx->GetHash().ToString(),
+                          tx->GetWitnessHash().ToString());
 }
 
-void CMainSignals::TransactionRemovedFromMempool(const CTransactionRef &ptx) {
-    auto event = [ptx, this] {
-        m_internals->Iterate([&](CValidationInterface& callbacks) { callbacks.TransactionRemovedFromMempool(ptx); });
+void CMainSignals::TransactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {
+    auto event = [tx, reason, this] {
+        m_internals->Iterate([&](CValidationInterface& callbacks) { callbacks.TransactionRemovedFromMempool(tx, reason); });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: txid=%s wtxid=%s", __func__,
-                          ptx->GetHash().ToString(),
-                          ptx->GetWitnessHash().ToString());
+                          tx->GetHash().ToString(),
+                          tx->GetWitnessHash().ToString());
 }
 
 void CMainSignals::BlockConnected(const std::shared_ptr<const CBlock> &pblock, const CBlockIndex *pindex) {
diff --git a/src/validationinterface.h b/src/validationinterface.h
index cb0204a555..3ab82306a6 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -21,6 +21,7 @@ class CConnman;
 class CValidationInterface;
 class uint256;
 class CScheduler;
+enum class MemPoolRemovalReason;
 
 // These functions dispatch to one or all registered wallets
 
@@ -96,7 +97,7 @@ protected:
      *
      * Called on a background thread.
      */
-    virtual void TransactionAddedToMempool(const CTransactionRef &ptxn) {}
+    virtual void TransactionAddedToMempool(const CTransactionRef& tx) {}
     /**
      * Notifies listeners of a transaction leaving mempool.
      *
@@ -129,7 +130,7 @@ protected:
      *
      * Called on a background thread.
      */
-    virtual void TransactionRemovedFromMempool(const CTransactionRef &ptx) {}
+    virtual void TransactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {}
     /**
      * Notifies listeners of a block being connected.
      * Provides a vector of transactions evicted from the mempool as a result.
@@ -196,8 +197,8 @@ public:
 
 
     void UpdatedBlockTip(const CBlockIndex *, const CBlockIndex *, bool fInitialDownload);
-    void TransactionAddedToMempool(const CTransactionRef &);
-    void TransactionRemovedFromMempool(const CTransactionRef &);
+    void TransactionAddedToMempool(const CTransactionRef&);
+    void TransactionRemovedFromMempool(const CTransactionRef&, MemPoolRemovalReason);
     void BlockConnected(const std::shared_ptr<const CBlock> &, const CBlockIndex *pindex);
     void BlockDisconnected(const std::shared_ptr<const CBlock> &, const CBlockIndex* pindex);
     void ChainStateFlushed(const CBlockLocator &);
diff --git a/src/wallet/scriptpubkeyman.cpp b/src/wallet/scriptpubkeyman.cpp
index b96cb0aa1a..8863e394eb 100644
--- a/src/wallet/scriptpubkeyman.cpp
+++ b/src/wallet/scriptpubkeyman.cpp
@@ -536,11 +536,6 @@ TransactionError LegacyScriptPubKeyMan::FillPSBT(PartiallySignedTransaction& psb
             continue;
         }
 
-        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
-        if (!input.IsSane()) {
-            return TransactionError::INVALID_PSBT;
-        }
-
         // Get the Sighash type
         if (sign && input.sighash_type > 0 && input.sighash_type != sighash_type) {
             return TransactionError::SIGHASH_MISMATCH;
diff --git a/src/wallet/test/psbt_wallet_tests.cpp b/src/wallet/test/psbt_wallet_tests.cpp
index 8b7b7af21d..f751ba5a3a 100644
--- a/src/wallet/test/psbt_wallet_tests.cpp
+++ b/src/wallet/test/psbt_wallet_tests.cpp
@@ -66,7 +66,7 @@ BOOST_AUTO_TEST_CASE(psbt_updater_test)
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
     std::string final_hex = HexStr(ssTx.begin(), ssTx.end());
-    BOOST_CHECK_EQUAL(final_hex, "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");
+    BOOST_CHECK_EQUAL(final_hex, "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");
 
     // Mutate the transaction so that one of the inputs is invalid
     psbtx.tx->vin[0].prevout.n = 2;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 45f5542cad..af3f958349 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -21,6 +21,7 @@
 #include <script/descriptor.h>
 #include <script/script.h>
 #include <script/signingprovider.h>
+#include <txmempool.h>
 #include <util/bip32.h>
 #include <util/error.h>
 #include <util/fees.h>
@@ -100,9 +101,11 @@ std::unique_ptr<interfaces::Handler> HandleLoadWallet(LoadWalletFn load_wallet)
     return interfaces::MakeHandler([it] { LOCK(cs_wallets); g_load_wallet_fns.erase(it); });
 }
 
+static Mutex g_loading_wallet_mutex;
 static Mutex g_wallet_release_mutex;
 static std::condition_variable g_wallet_release_cv;
-static std::set<std::string> g_unloading_wallet_set;
+static std::set<std::string> g_loading_wallet_set GUARDED_BY(g_loading_wallet_mutex);
+static std::set<std::string> g_unloading_wallet_set GUARDED_BY(g_wallet_release_mutex);
 
 // Custom deleter for shared_ptr<CWallet>.
 static void ReleaseWallet(CWallet* wallet)
@@ -146,7 +149,8 @@ void UnloadWallet(std::shared_ptr<CWallet>&& wallet)
     }
 }
 
-std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const WalletLocation& location, std::string& error, std::vector<std::string>& warnings)
+namespace {
+std::shared_ptr<CWallet> LoadWalletInternal(interfaces::Chain& chain, const WalletLocation& location, std::string& error, std::vector<std::string>& warnings)
 {
     try {
         if (!CWallet::Verify(chain, location, false, error, warnings)) {
@@ -167,6 +171,19 @@ std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const WalletLocati
         return nullptr;
     }
 }
+} // namespace
+
+std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const WalletLocation& location, std::string& error, std::vector<std::string>& warnings)
+{
+    auto result = WITH_LOCK(g_loading_wallet_mutex, return g_loading_wallet_set.insert(location.GetName()));
+    if (!result.second) {
+        error = "Wallet already being loading.";
+        return nullptr;
+    }
+    auto wallet = LoadWalletInternal(chain, location, error, warnings);
+    WITH_LOCK(g_loading_wallet_mutex, g_loading_wallet_set.erase(result.first));
+    return wallet;
+}
 
 std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const std::string& name, std::string& error, std::vector<std::string>& warnings)
 {
@@ -1093,24 +1110,52 @@ void CWallet::SyncTransaction(const CTransactionRef& ptx, CWalletTx::Confirmatio
     MarkInputsDirty(ptx);
 }
 
-void CWallet::transactionAddedToMempool(const CTransactionRef& ptx) {
-    auto locked_chain = chain().lock();
+void CWallet::transactionAddedToMempool(const CTransactionRef& tx) {
     LOCK(cs_wallet);
-    CWalletTx::Confirmation confirm(CWalletTx::Status::UNCONFIRMED, /* block_height */ 0, {}, /* nIndex */ 0);
-    SyncTransaction(ptx, confirm);
+    SyncTransaction(tx, {CWalletTx::Status::UNCONFIRMED, /* block height */ 0, /* block hash */ {}, /* index */ 0});
 
-    auto it = mapWallet.find(ptx->GetHash());
+    auto it = mapWallet.find(tx->GetHash());
     if (it != mapWallet.end()) {
         it->second.fInMempool = true;
     }
 }
 
-void CWallet::transactionRemovedFromMempool(const CTransactionRef &ptx) {
+void CWallet::transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {
     LOCK(cs_wallet);
-    auto it = mapWallet.find(ptx->GetHash());
+    auto it = mapWallet.find(tx->GetHash());
     if (it != mapWallet.end()) {
         it->second.fInMempool = false;
     }
+    // Handle transactions that were removed from the mempool because they
+    // conflict with transactions in a newly connected block.
+    if (reason == MemPoolRemovalReason::CONFLICT) {
+        // Call SyncNotifications, so external -walletnotify notifications will
+        // be triggered for these transactions. Set Status::UNCONFIRMED instead
+        // of Status::CONFLICTED for a few reasons:
+        //
+        // 1. The transactionRemovedFromMempool callback does not currently
+        //    provide the conflicting block's hash and height, and for backwards
+        //    compatibility reasons it may not be not safe to store conflicted
+        //    wallet transactions with a null block hash. See
+        //    https://github.com/bitcoin/bitcoin/pull/18600#discussion_r420195993.
+        // 2. For most of these transactions, the wallet's internal conflict
+        //    detection in the blockConnected handler will subsequently call
+        //    MarkConflicted and update them with CONFLICTED status anyway. This
+        //    applies to any wallet transaction that has inputs spent in the
+        //    block, or that has ancestors in the wallet with inputs spent by
+        //    the block.
+        // 3. Longstanding behavior since the sync implementation in
+        //    https://github.com/bitcoin/bitcoin/pull/9371 and the prior sync
+        //    implementation before that was to mark these transactions
+        //    unconfirmed rather than conflicted.
+        //
+        // Nothing described above should be seen as an unchangeable requirement
+        // when improving this code in the future. The wallet's heuristics for
+        // distinguishing between conflicted and unconfirmed transactions are
+        // imperfect, and could be improved in general, see
+        // https://github.com/bitcoin-core/bitcoin-devwiki/wiki/Wallet-Transaction-Conflict-Tracking
+        SyncTransaction(tx, {CWalletTx::Status::UNCONFIRMED, /* block height */ 0, /* block hash */ {}, /* index */ 0});
+    }
 }
 
 void CWallet::blockConnected(const CBlock& block, int height)
@@ -1122,9 +1167,8 @@ void CWallet::blockConnected(const CBlock& block, int height)
     m_last_block_processed_height = height;
     m_last_block_processed = block_hash;
     for (size_t index = 0; index < block.vtx.size(); index++) {
-        CWalletTx::Confirmation confirm(CWalletTx::Status::CONFIRMED, height, block_hash, index);
-        SyncTransaction(block.vtx[index], confirm);
-        transactionRemovedFromMempool(block.vtx[index]);
+        SyncTransaction(block.vtx[index], {CWalletTx::Status::CONFIRMED, height, block_hash, (int)index});
+        transactionRemovedFromMempool(block.vtx[index], MemPoolRemovalReason::BLOCK);
     }
 }
 
@@ -1140,8 +1184,7 @@ void CWallet::blockDisconnected(const CBlock& block, int height)
     m_last_block_processed_height = height - 1;
     m_last_block_processed = block.hashPrevBlock;
     for (const CTransactionRef& ptx : block.vtx) {
-        CWalletTx::Confirmation confirm(CWalletTx::Status::UNCONFIRMED, /* block_height */ 0, {}, /* nIndex */ 0);
-        SyncTransaction(ptx, confirm);
+        SyncTransaction(ptx, {CWalletTx::Status::UNCONFIRMED, /* block height */ 0, /* block hash */ {}, /* index */ 0});
     }
 }
 
@@ -1690,8 +1733,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
                 break;
             }
             for (size_t posInBlock = 0; posInBlock < block.vtx.size(); ++posInBlock) {
-                CWalletTx::Confirmation confirm(CWalletTx::Status::CONFIRMED, *block_height, block_hash, posInBlock);
-                SyncTransaction(block.vtx[posInBlock], confirm, fUpdate);
+                SyncTransaction(block.vtx[posInBlock], {CWalletTx::Status::CONFIRMED, *block_height, block_hash, (int)posInBlock}, fUpdate);
             }
             // scan succeeded, record block as most recent successfully scanned
             result.last_scanned_block = block_hash;
@@ -2491,13 +2533,8 @@ TransactionError CWallet::FillPSBT(PartiallySignedTransaction& psbtx, bool& comp
             continue;
         }
 
-        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
-        if (!input.IsSane()) {
-            return TransactionError::INVALID_PSBT;
-        }
-
         // If we have no utxo, grab it from the wallet.
-        if (!input.non_witness_utxo && input.witness_utxo.IsNull()) {
+        if (!input.non_witness_utxo) {
             const uint256& txhash = txin.prevout.hash;
             const auto it = mapWallet.find(txhash);
             if (it != mapWallet.end()) {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 7446a4889a..9ca8e9e309 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -910,7 +910,7 @@ public:
         uint256 last_failed_block;
     };
     ScanResult ScanForWalletTransactions(const uint256& first_block, const uint256& last_block, const WalletRescanReserver& reserver, bool fUpdate);
-    void transactionRemovedFromMempool(const CTransactionRef &ptx) override;
+    void transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) override;
     void ReacceptWalletTransactions() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void ResendWalletTransactions();
     struct Balance {
diff --git a/test/functional/feature_notifications.py b/test/functional/feature_notifications.py
index 47200b6cc6..fb0c7ceed4 100755
--- a/test/functional/feature_notifications.py
+++ b/test/functional/feature_notifications.py
@@ -125,12 +125,7 @@ class NotificationsTest(BitcoinTestFramework):
 
             # Bump tx2 as bump2 and generate a block on node 0 while
             # disconnected, then reconnect and check for notifications on node 1
-            # about newly confirmed bump2 and newly conflicted tx2. Currently
-            # only the bump2 notification is sent. Ideally, notifications would
-            # be sent both for bump2 and tx2, which was the previous behavior
-            # before being broken by an accidental change in PR
-            # https://github.com/bitcoin/bitcoin/pull/16624. The bug is reported
-            # in issue https://github.com/bitcoin/bitcoin/issues/18325.
+            # about newly confirmed bump2 and newly conflicted tx2.
             disconnect_nodes(self.nodes[0], 1)
             bump2 = self.nodes[0].bumpfee(tx2)["txid"]
             self.nodes[0].generatetoaddress(1, ADDRESS_BCRT1_UNSPENDABLE)
@@ -138,7 +133,7 @@ class NotificationsTest(BitcoinTestFramework):
             assert_equal(tx2 in self.nodes[1].getrawmempool(), True)
             connect_nodes(self.nodes[0], 1)
             self.sync_blocks()
-            self.expect_wallet_notify([bump2])
+            self.expect_wallet_notify([bump2, tx2])
             assert_equal(self.nodes[1].gettransaction(bump2)["confirmations"], 1)
 
         # TODO: add test for `-alertnotify` large fork notifications
diff --git a/test/functional/rpc_psbt.py b/test/functional/rpc_psbt.py
index 3a63377545..b8586f255c 100755
--- a/test/functional/rpc_psbt.py
+++ b/test/functional/rpc_psbt.py
@@ -37,6 +37,7 @@ class PSBTTest(BitcoinTestFramework):
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
 
+    # TODO: Re-enable this test with segwit v1
     def test_utxo_conversion(self):
         mining_node = self.nodes[2]
         offline_node = self.nodes[0]
@@ -133,6 +134,10 @@ class PSBTTest(BitcoinTestFramework):
         # spend single key from node 1
         rawtx = self.nodes[1].walletcreatefundedpsbt([{"txid":txid,"vout":p2wpkh_pos},{"txid":txid,"vout":p2sh_p2wpkh_pos},{"txid":txid,"vout":p2pkh_pos}], {self.nodes[1].getnewaddress():29.99})['psbt']
         walletprocesspsbt_out = self.nodes[1].walletprocesspsbt(rawtx)
+        # Make sure it has both types of UTXOs
+        decoded = self.nodes[1].decodepsbt(walletprocesspsbt_out['psbt'])
+        assert 'non_witness_utxo' in decoded['inputs'][0]
+        assert 'witness_utxo' in decoded['inputs'][0]
         assert_equal(walletprocesspsbt_out['complete'], True)
         self.nodes[1].sendrawtransaction(self.nodes[1].finalizepsbt(walletprocesspsbt_out['psbt'])['hex'])
 
@@ -326,7 +331,8 @@ class PSBTTest(BitcoinTestFramework):
         for i, signer in enumerate(signers):
             self.nodes[2].unloadwallet("wallet{}".format(i))
 
-        self.test_utxo_conversion()
+        # TODO: Re-enable this for segwit v1
+        # self.test_utxo_conversion()
 
         # Test that psbts with p2pkh outputs are created properly
         p2pkh = self.nodes[0].getnewaddress(address_type='legacy')
diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
index a2c502f280..294de76b7b 100755
--- a/test/functional/wallet_multiwallet.py
+++ b/test/functional/wallet_multiwallet.py
@@ -6,19 +6,36 @@
 
 Verify that a bitcoind node can load multiple wallet files
 """
+from threading import Thread
 import os
 import shutil
 import time
 
+from test_framework.authproxy import JSONRPCException
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.test_node import ErrorMatch
 from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
+    get_rpc_proxy,
 )
 
 FEATURE_LATEST = 169900
 
+got_loading_error = False
+def test_load_unload(node, name):
+    global got_loading_error
+    for i in range(10):
+        if got_loading_error:
+            return
+        try:
+            node.loadwallet(name)
+            node.unloadwallet(name)
+        except JSONRPCException as e:
+            if e.error['code'] == -4 and 'Wallet already being loading' in e.error['message']:
+                got_loading_error = True
+                return
+
 
 class MultiWalletTest(BitcoinTestFramework):
     def set_test_params(self):
@@ -219,6 +236,18 @@ class MultiWalletTest(BitcoinTestFramework):
         w2 = node.get_wallet_rpc(wallet_names[1])
         w2.getwalletinfo()
 
+        self.log.info("Concurrent wallet loading")
+        threads = []
+        for _ in range(3):
+            n = node.cli if self.options.usecli else get_rpc_proxy(node.url, 1, timeout=600, coveragedir=node.coverage_dir)
+            t = Thread(target=test_load_unload, args=(n, wallet_names[2], ))
+            t.start()
+            threads.append(t)
+        for t in threads:
+            t.join()
+        global got_loading_error
+        assert_equal(got_loading_error, True)
+
         self.log.info("Load remaining wallets")
         for wallet_name in wallet_names[2:]:
             loadwallet_name = self.nodes[0].loadwallet(wallet_name)