27 files changed, 609 insertions, 336 deletions
diff --git a/.gitignore b/.gitignore
index a8722aa593..ce40019dc3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -114,3 +114,4 @@ share/BitcoindComparisonTool.jar
 /doc/doxygen/
 
 libbitcoinconsensus.pc
+contrib/devtools/split-debug.sh
diff --git a/build-aux/m4/ax_pthread.m4 b/build-aux/m4/ax_pthread.m4
index d218d1af73..4c4051ea37 100644
--- a/build-aux/m4/ax_pthread.m4
+++ b/build-aux/m4/ax_pthread.m4
@@ -82,7 +82,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 22
+#serial 23
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [
@@ -100,22 +100,22 @@ ax_pthread_ok=no
 # etcetera environment variables, and if threads linking works using
 # them:
 if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
-	ax_pthread_save_CC="$CC"
-	ax_pthread_save_CFLAGS="$CFLAGS"
-	ax_pthread_save_LIBS="$LIBS"
-	AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
-	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-	LIBS="$PTHREAD_LIBS $LIBS"
-	AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
-	AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes])
-	AC_MSG_RESULT([$ax_pthread_ok])
-	if test "x$ax_pthread_ok" = "xno"; then
-		PTHREAD_LIBS=""
-		PTHREAD_CFLAGS=""
-	fi
-	CC="$ax_pthread_save_CC"
-	CFLAGS="$ax_pthread_save_CFLAGS"
-	LIBS="$ax_pthread_save_LIBS"
+        ax_pthread_save_CC="$CC"
+        ax_pthread_save_CFLAGS="$CFLAGS"
+        ax_pthread_save_LIBS="$LIBS"
+        AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
+        AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes])
+        AC_MSG_RESULT([$ax_pthread_ok])
+        if test "x$ax_pthread_ok" = "xno"; then
+                PTHREAD_LIBS=""
+                PTHREAD_CFLAGS=""
+        fi
+        CC="$ax_pthread_save_CC"
+        CFLAGS="$ax_pthread_save_CFLAGS"
+        LIBS="$ax_pthread_save_LIBS"
 fi
 
 # We must check for the threads library under a number of different
@@ -152,50 +152,50 @@ ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --
 
 case $host_os in
 
-	freebsd*)
+        freebsd*)
 
-	# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
-	# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
+        # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
+        # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
 
-	ax_pthread_flags="-kthread lthread $ax_pthread_flags"
-	;;
+        ax_pthread_flags="-kthread lthread $ax_pthread_flags"
+        ;;
 
-	hpux*)
+        hpux*)
 
-	# From the cc(1) man page: "[-mt] Sets various -D flags to enable
-	# multi-threading and also sets -lpthread."
+        # From the cc(1) man page: "[-mt] Sets various -D flags to enable
+        # multi-threading and also sets -lpthread."
 
-	ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags"
-	;;
+        ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags"
+        ;;
 
-	openedition*)
+        openedition*)
 
-	# IBM z/OS requires a feature-test macro to be defined in order to
-	# enable POSIX threads at all, so give the user a hint if this is
-	# not set. (We don't define these ourselves, as they can affect
-	# other portions of the system API in unpredictable ways.)
+        # IBM z/OS requires a feature-test macro to be defined in order to
+        # enable POSIX threads at all, so give the user a hint if this is
+        # not set. (We don't define these ourselves, as they can affect
+        # other portions of the system API in unpredictable ways.)
 
-	AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING],
-	    [
-#	     if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS)
-	     AX_PTHREAD_ZOS_MISSING
-#	     endif
-	    ],
-	    [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])])
-	;;
+        AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING],
+            [
+#            if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS)
+             AX_PTHREAD_ZOS_MISSING
+#            endif
+            ],
+            [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])])
+        ;;
 
-	solaris*)
+        solaris*)
 
-	# On Solaris (at least, for some versions), libc contains stubbed
-	# (non-functional) versions of the pthreads routines, so link-based
-	# tests will erroneously succeed. (N.B.: The stubs are missing
-	# pthread_cleanup_push, or rather a function called by this macro,
-	# so we could check for that, but who knows whether they'll stub
-	# that too in a future libc.)  So we'll check first for the
-	# standard Solaris way of linking pthreads (-mt -lpthread).
+        # On Solaris (at least, for some versions), libc contains stubbed
+        # (non-functional) versions of the pthreads routines, so link-based
+        # tests will erroneously succeed. (N.B.: The stubs are missing
+        # pthread_cleanup_push, or rather a function called by this macro,
+        # so we could check for that, but who knows whether they'll stub
+        # that too in a future libc.)  So we'll check first for the
+        # standard Solaris way of linking pthreads (-mt -lpthread).
 
-	ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
-	;;
+        ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
+        ;;
 esac
 
 # GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
@@ -208,17 +208,17 @@ AS_IF([test "x$GCC" = "xyes"],
 # correctly enabled
 
 case $host_os in
-	darwin* | hpux* | linux* | osf* | solaris*)
-	ax_pthread_check_macro="_REENTRANT"
-	;;
+        darwin* | hpux* | linux* | osf* | solaris*)
+        ax_pthread_check_macro="_REENTRANT"
+        ;;
 
-	aix* | freebsd*)
-	ax_pthread_check_macro="_THREAD_SAFE"
-	;;
+        aix*)
+        ax_pthread_check_macro="_THREAD_SAFE"
+        ;;
 
-	*)
-	ax_pthread_check_macro="--"
-	;;
+        *)
+        ax_pthread_check_macro="--"
+        ;;
 esac
 AS_IF([test "x$ax_pthread_check_macro" = "x--"],
       [ax_pthread_check_cond=0],
@@ -231,13 +231,13 @@ AC_CACHE_CHECK([whether $CC is Clang],
     [ax_cv_PTHREAD_CLANG=no
      # Note that Autoconf sets GCC=yes for Clang as well as GCC
      if test "x$GCC" = "xyes"; then
-	AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
-	    [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
-#	     if defined(__clang__) && defined(__llvm__)
-	     AX_PTHREAD_CC_IS_CLANG
-#	     endif
-	    ],
-	    [ax_cv_PTHREAD_CLANG=yes])
+        AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
+            [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
+#            if defined(__clang__) && defined(__llvm__)
+             AX_PTHREAD_CC_IS_CLANG
+#            endif
+            ],
+            [ax_cv_PTHREAD_CLANG=yes])
      fi
     ])
 ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
@@ -249,222 +249,222 @@ ax_pthread_clang_warning=no
 
 if test "x$ax_pthread_clang" = "xyes"; then
 
-	# Clang takes -pthread; it has never supported any other flag
-
-	# (Note 1: This will need to be revisited if a system that Clang
-	# supports has POSIX threads in a separate library.  This tends not
-	# to be the way of modern systems, but it's conceivable.)
-
-	# (Note 2: On some systems, notably Darwin, -pthread is not needed
-	# to get POSIX threads support; the API is always present and
-	# active.  We could reasonably leave PTHREAD_CFLAGS empty.  But
-	# -pthread does define _REENTRANT, and while the Darwin headers
-	# ignore this macro, third-party headers might not.)
-
-	PTHREAD_CFLAGS="-pthread"
-	PTHREAD_LIBS=
-
-	ax_pthread_ok=yes
-
-	# However, older versions of Clang make a point of warning the user
-	# that, in an invocation where only linking and no compilation is
-	# taking place, the -pthread option has no effect ("argument unused
-	# during compilation").  They expect -pthread to be passed in only
-	# when source code is being compiled.
-	#
-	# Problem is, this is at odds with the way Automake and most other
-	# C build frameworks function, which is that the same flags used in
-	# compilation (CFLAGS) are also used in linking.  Many systems
-	# supported by AX_PTHREAD require exactly this for POSIX threads
-	# support, and in fact it is often not straightforward to specify a
-	# flag that is used only in the compilation phase and not in
-	# linking.  Such a scenario is extremely rare in practice.
-	#
-	# Even though use of the -pthread flag in linking would only print
-	# a warning, this can be a nuisance for well-run software projects
-	# that build with -Werror.  So if the active version of Clang has
-	# this misfeature, we search for an option to squash it.
-
-	AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread],
-	    [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG],
-	    [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
-	     # Create an alternate version of $ac_link that compiles and
-	     # links in two steps (.c -> .o, .o -> exe) instead of one
-	     # (.c -> exe), because the warning occurs only in the second
-	     # step
-	     ax_pthread_save_ac_link="$ac_link"
-	     ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
-	     ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
-	     ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
-	     ax_pthread_save_CFLAGS="$CFLAGS"
-	     for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
-		AS_IF([test "x$ax_pthread_try" = "xunknown"], [break])
-		CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
-		ac_link="$ax_pthread_save_ac_link"
-		AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
-		    [ac_link="$ax_pthread_2step_ac_link"
-		     AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
-			 [break])
-		    ])
-	     done
-	     ac_link="$ax_pthread_save_ac_link"
-	     CFLAGS="$ax_pthread_save_CFLAGS"
-	     AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no])
-	     ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
-	    ])
-
-	case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
-		no | unknown) ;;
-		*) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
-	esac
+        # Clang takes -pthread; it has never supported any other flag
+
+        # (Note 1: This will need to be revisited if a system that Clang
+        # supports has POSIX threads in a separate library.  This tends not
+        # to be the way of modern systems, but it's conceivable.)
+
+        # (Note 2: On some systems, notably Darwin, -pthread is not needed
+        # to get POSIX threads support; the API is always present and
+        # active.  We could reasonably leave PTHREAD_CFLAGS empty.  But
+        # -pthread does define _REENTRANT, and while the Darwin headers
+        # ignore this macro, third-party headers might not.)
+
+        PTHREAD_CFLAGS="-pthread"
+        PTHREAD_LIBS=
+
+        ax_pthread_ok=yes
+
+        # However, older versions of Clang make a point of warning the user
+        # that, in an invocation where only linking and no compilation is
+        # taking place, the -pthread option has no effect ("argument unused
+        # during compilation").  They expect -pthread to be passed in only
+        # when source code is being compiled.
+        #
+        # Problem is, this is at odds with the way Automake and most other
+        # C build frameworks function, which is that the same flags used in
+        # compilation (CFLAGS) are also used in linking.  Many systems
+        # supported by AX_PTHREAD require exactly this for POSIX threads
+        # support, and in fact it is often not straightforward to specify a
+        # flag that is used only in the compilation phase and not in
+        # linking.  Such a scenario is extremely rare in practice.
+        #
+        # Even though use of the -pthread flag in linking would only print
+        # a warning, this can be a nuisance for well-run software projects
+        # that build with -Werror.  So if the active version of Clang has
+        # this misfeature, we search for an option to squash it.
+
+        AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread],
+            [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG],
+            [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
+             # Create an alternate version of $ac_link that compiles and
+             # links in two steps (.c -> .o, .o -> exe) instead of one
+             # (.c -> exe), because the warning occurs only in the second
+             # step
+             ax_pthread_save_ac_link="$ac_link"
+             ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
+             ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+             ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
+             ax_pthread_save_CFLAGS="$CFLAGS"
+             for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
+                AS_IF([test "x$ax_pthread_try" = "xunknown"], [break])
+                CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
+                ac_link="$ax_pthread_save_ac_link"
+                AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
+                    [ac_link="$ax_pthread_2step_ac_link"
+                     AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
+                         [break])
+                    ])
+             done
+             ac_link="$ax_pthread_save_ac_link"
+             CFLAGS="$ax_pthread_save_CFLAGS"
+             AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no])
+             ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
+            ])
+
+        case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
+                no | unknown) ;;
+                *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
+        esac
 
 fi # $ax_pthread_clang = yes
 
 if test "x$ax_pthread_ok" = "xno"; then
 for ax_pthread_try_flag in $ax_pthread_flags; do
 
-	case $ax_pthread_try_flag in
-		none)
-		AC_MSG_CHECKING([whether pthreads work without any flags])
-		;;
-
-		-mt,pthread)
-		AC_MSG_CHECKING([whether pthreads work with -mt -lpthread])
-		PTHREAD_CFLAGS="-mt"
-		PTHREAD_LIBS="-lpthread"
-		;;
-
-		-*)
-		AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
-		PTHREAD_CFLAGS="$ax_pthread_try_flag"
-		;;
-
-		pthread-config)
-		AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
-		AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
-		PTHREAD_CFLAGS="`pthread-config --cflags`"
-		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
-		;;
-
-		*)
-		AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
-		PTHREAD_LIBS="-l$ax_pthread_try_flag"
-		;;
-	esac
-
-	ax_pthread_save_CFLAGS="$CFLAGS"
-	ax_pthread_save_LIBS="$LIBS"
-	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-	LIBS="$PTHREAD_LIBS $LIBS"
-
-	# Check for various functions.  We must include pthread.h,
-	# since some functions may be macros.  (On the Sequent, we
-	# need a special flag -Kthread to make this header compile.)
-	# We check for pthread_join because it is in -lpthread on IRIX
-	# while pthread_create is in libc.  We check for pthread_attr_init
-	# due to DEC craziness with -lpthreads.  We check for
-	# pthread_cleanup_push because it is one of the few pthread
-	# functions on Solaris that doesn't have a non-functional libc stub.
-	# We try pthread_create on general principles.
-
-	AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-#			if $ax_pthread_check_cond
-#			 error "$ax_pthread_check_macro must be defined"
-#			endif
-			static void routine(void *a) { a = 0; }
-			static void *start_routine(void *a) { return a; }],
-		       [pthread_t th; pthread_attr_t attr;
-			pthread_create(&th, 0, start_routine, 0);
-			pthread_join(th, 0);
-			pthread_attr_init(&attr);
-			pthread_cleanup_push(routine, 0);
-			pthread_cleanup_pop(0) /* ; */])],
-	    [ax_pthread_ok=yes],
-	    [])
-
-	CFLAGS="$ax_pthread_save_CFLAGS"
-	LIBS="$ax_pthread_save_LIBS"
-
-	AC_MSG_RESULT([$ax_pthread_ok])
-	AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
-
-	PTHREAD_LIBS=""
-	PTHREAD_CFLAGS=""
+        case $ax_pthread_try_flag in
+                none)
+                AC_MSG_CHECKING([whether pthreads work without any flags])
+                ;;
+
+                -mt,pthread)
+                AC_MSG_CHECKING([whether pthreads work with -mt -lpthread])
+                PTHREAD_CFLAGS="-mt"
+                PTHREAD_LIBS="-lpthread"
+                ;;
+
+                -*)
+                AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
+                PTHREAD_CFLAGS="$ax_pthread_try_flag"
+                ;;
+
+                pthread-config)
+                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
+                AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
+                PTHREAD_CFLAGS="`pthread-config --cflags`"
+                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+                ;;
+
+                *)
+                AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
+                PTHREAD_LIBS="-l$ax_pthread_try_flag"
+                ;;
+        esac
+
+        ax_pthread_save_CFLAGS="$CFLAGS"
+        ax_pthread_save_LIBS="$LIBS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+
+        # Check for various functions.  We must include pthread.h,
+        # since some functions may be macros.  (On the Sequent, we
+        # need a special flag -Kthread to make this header compile.)
+        # We check for pthread_join because it is in -lpthread on IRIX
+        # while pthread_create is in libc.  We check for pthread_attr_init
+        # due to DEC craziness with -lpthreads.  We check for
+        # pthread_cleanup_push because it is one of the few pthread
+        # functions on Solaris that doesn't have a non-functional libc stub.
+        # We try pthread_create on general principles.
+
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
+#                       if $ax_pthread_check_cond
+#                        error "$ax_pthread_check_macro must be defined"
+#                       endif
+                        static void routine(void *a) { a = 0; }
+                        static void *start_routine(void *a) { return a; }],
+                       [pthread_t th; pthread_attr_t attr;
+                        pthread_create(&th, 0, start_routine, 0);
+                        pthread_join(th, 0);
+                        pthread_attr_init(&attr);
+                        pthread_cleanup_push(routine, 0);
+                        pthread_cleanup_pop(0) /* ; */])],
+            [ax_pthread_ok=yes],
+            [])
+
+        CFLAGS="$ax_pthread_save_CFLAGS"
+        LIBS="$ax_pthread_save_LIBS"
+
+        AC_MSG_RESULT([$ax_pthread_ok])
+        AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
+
+        PTHREAD_LIBS=""
+        PTHREAD_CFLAGS=""
 done
 fi
 
 # Various other checks:
 if test "x$ax_pthread_ok" = "xyes"; then
-	ax_pthread_save_CFLAGS="$CFLAGS"
-	ax_pthread_save_LIBS="$LIBS"
-	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-	LIBS="$PTHREAD_LIBS $LIBS"
-
-	# Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
-	AC_CACHE_CHECK([for joinable pthread attribute],
-	    [ax_cv_PTHREAD_JOINABLE_ATTR],
-	    [ax_cv_PTHREAD_JOINABLE_ATTR=unknown
-	     for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
-		 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
-						 [int attr = $ax_pthread_attr; return attr /* ; */])],
-				[ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break],
-				[])
-	     done
-	    ])
-	AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \
-	       test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \
-	       test "x$ax_pthread_joinable_attr_defined" != "xyes"],
-	      [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE],
-				  [$ax_cv_PTHREAD_JOINABLE_ATTR],
-				  [Define to necessary symbol if this constant
-				   uses a non-standard name on your system.])
-	       ax_pthread_joinable_attr_defined=yes
-	      ])
-
-	AC_CACHE_CHECK([whether more special flags are required for pthreads],
-	    [ax_cv_PTHREAD_SPECIAL_FLAGS],
-	    [ax_cv_PTHREAD_SPECIAL_FLAGS=no
-	     case $host_os in
-	     solaris*)
-	     ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
-	     ;;
-	     esac
-	    ])
-	AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \
-	       test "x$ax_pthread_special_flags_added" != "xyes"],
-	      [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS"
-	       ax_pthread_special_flags_added=yes])
-
-	AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
-	    [ax_cv_PTHREAD_PRIO_INHERIT],
-	    [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
-					     [[int i = PTHREAD_PRIO_INHERIT;]])],
-			    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
-			    [ax_cv_PTHREAD_PRIO_INHERIT=no])
-	    ])
-	AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \
-	       test "x$ax_pthread_prio_inherit_defined" != "xyes"],
-	      [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])
-	       ax_pthread_prio_inherit_defined=yes
-	      ])
-
-	CFLAGS="$ax_pthread_save_CFLAGS"
-	LIBS="$ax_pthread_save_LIBS"
-
-	# More AIX lossage: compile with *_r variant
-	if test "x$GCC" != "xyes"; then
-	    case $host_os in
-		aix*)
-		AS_CASE(["x/$CC"],
-		    [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
-		    [#handle absolute path differently from PATH based program lookup
-		     AS_CASE(["x$CC"],
-			 [x/*],
-			 [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
-			 [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
-		;;
-	    esac
-	fi
+        ax_pthread_save_CFLAGS="$CFLAGS"
+        ax_pthread_save_LIBS="$LIBS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+
+        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
+        AC_CACHE_CHECK([for joinable pthread attribute],
+            [ax_cv_PTHREAD_JOINABLE_ATTR],
+            [ax_cv_PTHREAD_JOINABLE_ATTR=unknown
+             for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
+                 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
+                                                 [int attr = $ax_pthread_attr; return attr /* ; */])],
+                                [ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break],
+                                [])
+             done
+            ])
+        AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \
+               test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \
+               test "x$ax_pthread_joinable_attr_defined" != "xyes"],
+              [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE],
+                                  [$ax_cv_PTHREAD_JOINABLE_ATTR],
+                                  [Define to necessary symbol if this constant
+                                   uses a non-standard name on your system.])
+               ax_pthread_joinable_attr_defined=yes
+              ])
+
+        AC_CACHE_CHECK([whether more special flags are required for pthreads],
+            [ax_cv_PTHREAD_SPECIAL_FLAGS],
+            [ax_cv_PTHREAD_SPECIAL_FLAGS=no
+             case $host_os in
+             solaris*)
+             ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
+             ;;
+             esac
+            ])
+        AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \
+               test "x$ax_pthread_special_flags_added" != "xyes"],
+              [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS"
+               ax_pthread_special_flags_added=yes])
+
+        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
+            [ax_cv_PTHREAD_PRIO_INHERIT],
+            [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
+                                             [[int i = PTHREAD_PRIO_INHERIT;]])],
+                            [ax_cv_PTHREAD_PRIO_INHERIT=yes],
+                            [ax_cv_PTHREAD_PRIO_INHERIT=no])
+            ])
+        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \
+               test "x$ax_pthread_prio_inherit_defined" != "xyes"],
+              [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])
+               ax_pthread_prio_inherit_defined=yes
+              ])
+
+        CFLAGS="$ax_pthread_save_CFLAGS"
+        LIBS="$ax_pthread_save_LIBS"
+
+        # More AIX lossage: compile with *_r variant
+        if test "x$GCC" != "xyes"; then
+            case $host_os in
+                aix*)
+                AS_CASE(["x/$CC"],
+                    [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
+                    [#handle absolute path differently from PATH based program lookup
+                     AS_CASE(["x$CC"],
+                         [x/*],
+                         [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
+                         [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+                ;;
+            esac
+        fi
 fi
 
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
@@ -475,11 +475,11 @@ AC_SUBST([PTHREAD_CC])
 
 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
 if test "x$ax_pthread_ok" = "xyes"; then
-	ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
-	:
+        ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
+        :
 else
-	ax_pthread_ok=no
-	$2
+        ax_pthread_ok=no
+        $2
 fi
 AC_LANG_POP
 ])dnl AX_PTHREAD
diff --git a/contrib/gitian-descriptors/gitian-linux.yml b/contrib/gitian-descriptors/gitian-linux.yml
index fb629578d6..a2788c9d76 100644
--- a/contrib/gitian-descriptors/gitian-linux.yml
+++ b/contrib/gitian-descriptors/gitian-linux.yml
@@ -84,11 +84,11 @@ script: |
   done
   }
 
-  export PATH=${WRAP_DIR}:${PATH}
-
   # Faketime for depends so intermediate results are comparable
+  export PATH_orig=${PATH}
   create_global_faketime_wrappers "2000-01-01 12:00:00"
   create_per-host_faketime_wrappers "2000-01-01 12:00:00"
+  export PATH=${WRAP_DIR}:${PATH}
 
   cd bitcoin
   BASEPREFIX=`pwd`/depends
@@ -98,8 +98,10 @@ script: |
   done
 
   # Faketime for binaries
+  export PATH=${PATH_orig}
   create_global_faketime_wrappers "${REFERENCE_DATETIME}"
   create_per-host_faketime_wrappers "${REFERENCE_DATETIME}"
+  export PATH=${WRAP_DIR}:${PATH}
 
   # Create the release tarball using (arbitrarily) the first host
   ./autogen.sh
diff --git a/contrib/gitian-descriptors/gitian-osx.yml b/contrib/gitian-descriptors/gitian-osx.yml
index 8436cd612a..536fcfb105 100644
--- a/contrib/gitian-descriptors/gitian-osx.yml
+++ b/contrib/gitian-descriptors/gitian-osx.yml
@@ -77,11 +77,11 @@ script: |
   done
   }
 
-  export PATH=${WRAP_DIR}:${PATH}
-
   # Faketime for depends so intermediate results are comparable
+  export PATH_orig=${PATH}
   create_global_faketime_wrappers "2000-01-01 12:00:00"
   create_per-host_faketime_wrappers "2000-01-01 12:00:00"
+  export PATH=${WRAP_DIR}:${PATH}
 
   cd bitcoin
   BASEPREFIX=`pwd`/depends
@@ -95,8 +95,10 @@ script: |
   done
 
   # Faketime for binaries
+  export PATH=${PATH_orig}
   create_global_faketime_wrappers "${REFERENCE_DATETIME}"
   create_per-host_faketime_wrappers "${REFERENCE_DATETIME}"
+  export PATH=${WRAP_DIR}:${PATH}
 
   # Create the release tarball using (arbitrarily) the first host
   ./autogen.sh
diff --git a/contrib/gitian-descriptors/gitian-win.yml b/contrib/gitian-descriptors/gitian-win.yml
index 1d3a876dfb..32b57b3160 100644
--- a/contrib/gitian-descriptors/gitian-win.yml
+++ b/contrib/gitian-descriptors/gitian-win.yml
@@ -94,12 +94,12 @@ script: |
   done
   }
 
-  export PATH=${WRAP_DIR}:${PATH}
-
   # Faketime for depends so intermediate results are comparable
+  export PATH_orig=${PATH}
   create_global_faketime_wrappers "2000-01-01 12:00:00"
   create_per-host_faketime_wrappers "2000-01-01 12:00:00"
   create_per-host_linker_wrapper "2000-01-01 12:00:00"
+  export PATH=${WRAP_DIR}:${PATH}
 
   cd bitcoin
   BASEPREFIX=`pwd`/depends
@@ -109,9 +109,11 @@ script: |
   done
 
   # Faketime for binaries
+  export PATH=${PATH_orig}
   create_global_faketime_wrappers "${REFERENCE_DATETIME}"
   create_per-host_faketime_wrappers "${REFERENCE_DATETIME}"
   create_per-host_linker_wrapper "${REFERENCE_DATETIME}"
+  export PATH=${WRAP_DIR}:${PATH}
 
   # Create the release tarball using (arbitrarily) the first host
   ./autogen.sh
diff --git a/doc/bips.md b/doc/bips.md
index b4b62e781e..1ec03d2fb1 100644
--- a/doc/bips.md
+++ b/doc/bips.md
@@ -10,6 +10,7 @@ BIPs that are implemented by Bitcoin Core (up-to-date up to **v0.13.0**):
 * [`BIP 23`](https://github.com/bitcoin/bips/blob/master/bip-0023.mediawiki): Some extensions to GBT have been implemented since **v0.10.0rc1**, including longpolling and block proposals ([PR #1816](https://github.com/bitcoin/bitcoin/pull/1816)).
 * [`BIP 30`](https://github.com/bitcoin/bips/blob/master/bip-0030.mediawiki): The evaluation rules to forbid creating new transactions with the same txid as previous not-fully-spent transactions were implemented since **v0.6.0**, and the rule took effect on *March 15th 2012* ([PR #915](https://github.com/bitcoin/bitcoin/pull/915)).
 * [`BIP 31`](https://github.com/bitcoin/bips/blob/master/bip-0031.mediawiki): The 'pong' protocol message (and the protocol version bump to 60001) has been implemented since **v0.6.1** ([PR #1081](https://github.com/bitcoin/bitcoin/pull/1081)).
+* [`BIP 32`](https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki): Hierarchical Deterministic Wallets has been implemented since **v0.13.0** ([PR #8035](https://github.com/bitcoin/bitcoin/pull/8035)).
 * [`BIP 34`](https://github.com/bitcoin/bips/blob/master/bip-0034.mediawiki): The rule that requires blocks to contain their height (number) in the coinbase input, and the introduction of version 2 blocks has been implemented since **v0.7.0**. The rule took effect for version 2 blocks as of *block 224413* (March 5th 2013), and version 1 blocks are no longer allowed since *block 227931* (March 25th 2013) ([PR #1526](https://github.com/bitcoin/bitcoin/pull/1526)).
 * [`BIP 35`](https://github.com/bitcoin/bips/blob/master/bip-0035.mediawiki): The 'mempool' protocol message (and the protocol version bump to 60002) has been implemented since **v0.7.0** ([PR #1641](https://github.com/bitcoin/bitcoin/pull/1641)).
 * [`BIP 37`](https://github.com/bitcoin/bips/blob/master/bip-0037.mediawiki): The bloom filtering for transaction relaying, partial merkle trees for blocks, and the protocol version bump to 70001 (enabling low-bandwidth SPV clients) has been implemented since **v0.8.0** ([PR #1795](https://github.com/bitcoin/bitcoin/pull/1795)).
diff --git a/doc/release-notes.md b/doc/release-notes.md
index be619e41c6..491c82b693 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -119,6 +119,24 @@ feerate. [BIP 133](https://github.com/bitcoin/bips/blob/master/bip-0133.mediawik
 
 ### Wallet
 
+Hierarchical Deterministic Key Generation
+-----------------------------------------
+Newly created wallets will use hierarchical deterministic key generation
+according to BIP32 (keypath m/0'/0'/k').
+Existing wallets will still use traditional key generation.
+
+Backups of HD wallets, regardless of when they have been created, can
+therefore be used to re-generate all possible private keys, even the
+ones which haven't already been generated during the time of the backup.
+
+HD key generation for new wallets can be disabled by `-usehd=0`. Keep in
+mind that this flag only has affect on newly created wallets.
+You can't disable HD key generation once you have created a HD wallet.
+
+There is no distinction between internal (change) and external keys.
+
+[Pull request](https://github.com/bitcoin/bitcoin/pull/8035/files), [BIP 32](https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki)
+
 ### GUI
 
 ### Tests
diff --git a/qa/rpc-tests/fundrawtransaction.py b/qa/rpc-tests/fundrawtransaction.py
index 998f822afe..228574e671 100755
--- a/qa/rpc-tests/fundrawtransaction.py
+++ b/qa/rpc-tests/fundrawtransaction.py
@@ -58,7 +58,6 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 1.0)
         self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 5.0)
 
-        self.sync_all()
         self.nodes[0].generate(1)
         self.sync_all()
 
@@ -552,7 +551,6 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.nodes[1].walletpassphrase("test", 100)
         signedTx = self.nodes[1].signrawtransaction(fundedTx['hex'])
         txId = self.nodes[1].sendrawtransaction(signedTx['hex'])
-        self.sync_all()
         self.nodes[1].generate(1)
         self.sync_all()
 
@@ -572,7 +570,6 @@ class RawTransactionsTest(BitcoinTestFramework):
 
         for i in range(0,20):
             self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.01)
-        self.sync_all()
         self.nodes[0].generate(1)
         self.sync_all()
 
@@ -603,7 +600,6 @@ class RawTransactionsTest(BitcoinTestFramework):
 
         for i in range(0,20):
             self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.01)
-        self.sync_all()
         self.nodes[0].generate(1)
         self.sync_all()
 
@@ -677,6 +673,15 @@ class RawTransactionsTest(BitcoinTestFramework):
         signedtx = self.nodes[0].signrawtransaction(signedtx["hex"])
         assert(signedtx["complete"])
         self.nodes[0].sendrawtransaction(signedtx["hex"])
+        self.nodes[0].generate(1)
+        self.sync_all()
+
+        #######################
+        # Test feeRate option #
+        #######################
+
+        # Make sure there is exactly one input so coin selection can't skew the result
+        assert_equal(len(self.nodes[3].listunspent(1)), 1)
 
         inputs = []
         outputs = {self.nodes[2].getnewaddress() : 1}
@@ -684,8 +689,9 @@ class RawTransactionsTest(BitcoinTestFramework):
         result = self.nodes[3].fundrawtransaction(rawtx) # uses min_relay_tx_fee (set by settxfee)
         result2 = self.nodes[3].fundrawtransaction(rawtx, {"feeRate": 2*min_relay_tx_fee})
         result3 = self.nodes[3].fundrawtransaction(rawtx, {"feeRate": 10*min_relay_tx_fee})
-        assert_equal(result['fee']*2, result2['fee'])
-        assert_equal(result['fee']*10, result3['fee'])
+        result_fee_rate = result['fee'] * 1000 / count_bytes(result['hex'])
+        assert_fee_amount(result2['fee'], count_bytes(result2['hex']), 2 * result_fee_rate)
+        assert_fee_amount(result3['fee'], count_bytes(result3['hex']), 10 * result_fee_rate)
 
 if __name__ == '__main__':
     RawTransactionsTest().main()
diff --git a/qa/rpc-tests/rawtransactions.py b/qa/rpc-tests/rawtransactions.py
index aa403f058c..ab6d2e8def 100755
--- a/qa/rpc-tests/rawtransactions.py
+++ b/qa/rpc-tests/rawtransactions.py
@@ -143,6 +143,20 @@ class RawTransactionsTest(BitcoinTestFramework):
         rawtx   = self.nodes[0].createrawtransaction(inputs, outputs)
         decrawtx= self.nodes[0].decoderawtransaction(rawtx)
         assert_equal(decrawtx['vin'][0]['sequence'], 1000)
+        
+        inputs  = [ {'txid' : "1d1d4e24ed99057e84c3f80fd8fbec79ed9e1acee37da269356ecea000000000", 'vout' : 1, 'sequence' : -1}]
+        outputs = { self.nodes[0].getnewaddress() : 1 }
+        assert_raises(JSONRPCException, self.nodes[0].createrawtransaction, inputs, outputs)
+        
+        inputs  = [ {'txid' : "1d1d4e24ed99057e84c3f80fd8fbec79ed9e1acee37da269356ecea000000000", 'vout' : 1, 'sequence' : 4294967296}]
+        outputs = { self.nodes[0].getnewaddress() : 1 }
+        assert_raises(JSONRPCException, self.nodes[0].createrawtransaction, inputs, outputs)
+        
+        inputs  = [ {'txid' : "1d1d4e24ed99057e84c3f80fd8fbec79ed9e1acee37da269356ecea000000000", 'vout' : 1, 'sequence' : 4294967294}]
+        outputs = { self.nodes[0].getnewaddress() : 1 }
+        rawtx   = self.nodes[0].createrawtransaction(inputs, outputs)
+        decrawtx= self.nodes[0].decoderawtransaction(rawtx)
+        assert_equal(decrawtx['vin'][0]['sequence'], 4294967294)
 
 if __name__ == '__main__':
     RawTransactionsTest().main()
diff --git a/qa/rpc-tests/test_framework/util.py b/qa/rpc-tests/test_framework/util.py
index fc66ef287d..782df52d62 100644
--- a/qa/rpc-tests/test_framework/util.py
+++ b/qa/rpc-tests/test_framework/util.py
@@ -477,6 +477,15 @@ def random_transaction(nodes, amount, min_fee, fee_increment, fee_variants):
 
     return (txid, signresult["hex"], fee)
 
+def assert_fee_amount(fee, tx_size, fee_per_kB):
+    """Assert the fee was in range"""
+    target_fee = tx_size * fee_per_kB / 1000
+    if fee < target_fee:
+        raise AssertionError("Fee of %s BTC too low! (Should be %s BTC)"%(str(fee), str(target_fee)))
+    # allow the wallet's estimation to be at most 2 bytes off
+    if fee > (tx_size + 2) * fee_per_kB / 1000:
+        raise AssertionError("Fee of %s BTC too high! (Should be %s BTC)"%(str(fee), str(target_fee)))
+
 def assert_equal(thing1, thing2):
     if thing1 != thing2:
         raise AssertionError("%s != %s"%(str(thing1),str(thing2)))
diff --git a/qa/rpc-tests/wallet.py b/qa/rpc-tests/wallet.py
index 9dda712f4f..0b7eb52f07 100755
--- a/qa/rpc-tests/wallet.py
+++ b/qa/rpc-tests/wallet.py
@@ -11,12 +11,7 @@ class WalletTest (BitcoinTestFramework):
     def check_fee_amount(self, curr_balance, balance_with_fee, fee_per_byte, tx_size):
         """Return curr_balance after asserting the fee was in range"""
         fee = balance_with_fee - curr_balance
-        target_fee = fee_per_byte * tx_size
-        if fee < target_fee:
-            raise AssertionError("Fee of %s BTC too low! (Should be %s BTC)"%(str(fee), str(target_fee)))
-        # allow the node's estimation to be at most 2 bytes off
-        if fee > fee_per_byte * (tx_size + 2):
-            raise AssertionError("Fee of %s BTC too high! (Should be %s BTC)"%(str(fee), str(target_fee)))
+        assert_fee_amount(fee, tx_size, fee_per_byte * 1000)
         return curr_balance
 
     def __init__(self):
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 0005115671..8c27a578bb 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -16,14 +16,6 @@
 
 #include "chainparamsseeds.h"
 
-std::string CDNSSeedData::getHost(uint64_t requiredServiceBits) const {
-    //use default host for non-filter-capable seeds or if we use the default service bits (NODE_NETWORK)
-    if (!supportsServiceBitsFiltering || requiredServiceBits == NODE_NETWORK)
-        return host;
-    
-    return strprintf("x%x.%s", requiredServiceBits, host);
-}
-
 static CBlock CreateGenesisBlock(const char* pszTimestamp, const CScript& genesisOutputScript, uint32_t nTime, uint32_t nNonce, uint32_t nBits, int32_t nVersion, const CAmount& genesisReward)
 {
     CMutableTransaction txNew;
diff --git a/src/chainparams.h b/src/chainparams.h
index 7168daaf43..638893e9ad 100644
--- a/src/chainparams.h
+++ b/src/chainparams.h
@@ -13,11 +13,9 @@
 
 #include <vector>
 
-class CDNSSeedData {
-public:
+struct CDNSSeedData {
     std::string name, host;
     bool supportsServiceBitsFiltering;
-    std::string getHost(uint64_t requiredServiceBits) const;
     CDNSSeedData(const std::string &strName, const std::string &strHost, bool supportsServiceBitsFilteringIn = false) : name(strName), host(strHost), supportsServiceBitsFiltering(supportsServiceBitsFilteringIn) {}
 };
 
diff --git a/src/init.cpp b/src/init.cpp
index c2ba9ae44b..b572bfc327 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -479,11 +479,20 @@ std::string HelpMessage(HelpMessageMode mode)
 
 std::string LicenseInfo()
 {
+    const std::string URL_SOURCE_CODE = "<https://github.com/bitcoin/bitcoin>";
+    const std::string URL_WEBSITE = "<https://bitcoincore.org>";
     // todo: remove urls from translations on next change
     return CopyrightHolders(strprintf(_("Copyright (C) %i-%i"), 2009, COPYRIGHT_YEAR) + " ") + "\n" +
            "\n" +
-           _("This is experimental software.") + "\n" +
+           strprintf(_("Please contribute if you find %s useful. "
+                       "Visit %s for further information about the software."),
+               PACKAGE_NAME, URL_WEBSITE) +
+           "\n" +
+           strprintf(_("The source code is available from %s."),
+               URL_SOURCE_CODE) +
            "\n" +
+           "\n" +
+           _("This is experimental software.") + "\n" +
            _("Distributed under the MIT software license, see the accompanying file COPYING or <http://www.opensource.org/licenses/mit-license.php>.") + "\n" +
            "\n" +
            _("This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit <https://www.openssl.org/> and cryptographic software written by Eric Young and UPnP software written by Thomas Bernard.") +
diff --git a/src/main.cpp b/src/main.cpp
index 62012bf567..bdb3457f8e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3449,8 +3449,9 @@ static bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state
 }
 
 /** Store block on disk. If dbp is non-NULL, the file is known to already reside on disk */
-static bool AcceptBlock(const CBlock& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp)
+static bool AcceptBlock(const CBlock& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp, bool* fNewBlock)
 {
+    if (fNewBlock) *fNewBlock = false;
     AssertLockHeld(cs_main);
 
     CBlockIndex *pindexDummy = NULL;
@@ -3479,6 +3480,7 @@ static bool AcceptBlock(const CBlock& block, CValidationState& state, const CCha
         if (!fHasMoreWork) return true;     // Don't process less-work chains
         if (fTooFarAhead) return true;      // Block height is too high
     }
+    if (fNewBlock) *fNewBlock = true;
 
     if ((!CheckBlock(block, state, chainparams.GetConsensus(), GetAdjustedTime())) || !ContextualCheckBlock(block, state, pindex->pprev)) {
         if (state.IsInvalid() && !state.CorruptionPossible()) {
@@ -3526,7 +3528,7 @@ static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned
 }
 
 
-bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, const CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp)
+bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp)
 {
     {
         LOCK(cs_main);
@@ -3535,9 +3537,11 @@ bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, c
 
         // Store to disk
         CBlockIndex *pindex = NULL;
-        bool ret = AcceptBlock(*pblock, state, chainparams, &pindex, fRequested, dbp);
+        bool fNewBlock = false;
+        bool ret = AcceptBlock(*pblock, state, chainparams, &pindex, fRequested, dbp, &fNewBlock);
         if (pindex && pfrom) {
             mapBlockSource[pindex->GetBlockHash()] = pfrom->GetId();
+            if (fNewBlock) pfrom->nLastBlockTime = GetTime();
         }
         CheckBlockIndex(chainparams.GetConsensus());
         if (!ret)
@@ -4107,7 +4111,7 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
                 if (mapBlockIndex.count(hash) == 0 || (mapBlockIndex[hash]->nStatus & BLOCK_HAVE_DATA) == 0) {
                     LOCK(cs_main);
                     CValidationState state;
-                    if (AcceptBlock(block, state, chainparams, NULL, true, dbp))
+                    if (AcceptBlock(block, state, chainparams, NULL, true, dbp, NULL))
                         nLoaded++;
                     if (state.IsError())
                         break;
@@ -4140,7 +4144,7 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
                                     head.ToString());
                             LOCK(cs_main);
                             CValidationState dummy;
-                            if (AcceptBlock(block, dummy, chainparams, NULL, true, &it->second))
+                            if (AcceptBlock(block, dummy, chainparams, NULL, true, &it->second, NULL))
                             {
                                 nLoaded++;
                                 queue.push_back(block.GetHash());
@@ -5058,6 +5062,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             RelayTransaction(tx);
             vWorkQueue.push_back(inv.hash);
 
+            pfrom->nLastTXTime = GetTime();
+
             LogPrint("mempool", "AcceptToMemoryPool: peer=%d: accepted %s (poolsz %u txn, %u kB)\n",
                 pfrom->id,
                 tx.GetHash().ToString(),
diff --git a/src/main.h b/src/main.h
index 9b99ae7c87..e2bfdfdf6e 100644
--- a/src/main.h
+++ b/src/main.h
@@ -215,7 +215,7 @@ void UnregisterNodeSignals(CNodeSignals& nodeSignals);
  * @param[out]  dbp     The already known disk position of pblock, or NULL if not yet stored.
  * @return True if state.IsValid()
  */
-bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, const CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp);
+bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp);
 /** Check whether enough disk space is available for an incoming block */
 bool CheckDiskSpace(uint64_t nAdditionalBytes = 0);
 /** Open a block file (blk?????.dat) */
diff --git a/src/net.cpp b/src/net.cpp
index 30a6bc896d..4eca3d75cc 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -861,6 +861,11 @@ struct NodeEvictionCandidate
     NodeId id;
     int64_t nTimeConnected;
     int64_t nMinPingUsecTime;
+    int64_t nLastBlockTime;
+    int64_t nLastTXTime;
+    bool fNetworkNode;
+    bool fRelayTxes;
+    bool fBloomFilter;
     CAddress addr;
     uint64_t nKeyedNetGroup;
 };
@@ -877,7 +882,24 @@ static bool ReverseCompareNodeTimeConnected(const NodeEvictionCandidate &a, cons
 
 static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) {
     return a.nKeyedNetGroup < b.nKeyedNetGroup;
-};
+}
+
+static bool CompareNodeBlockTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
+{
+    // There is a fall-through here because it is common for a node to have many peers which have not yet relayed a block.
+    if (a.nLastBlockTime != b.nLastBlockTime) return a.nLastBlockTime < b.nLastBlockTime;
+    if (a.fNetworkNode != b.fNetworkNode) return b.fNetworkNode;
+    return a.nTimeConnected > b.nTimeConnected;
+}
+
+static bool CompareNodeTXTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
+{
+    // There is a fall-through here because it is common for a node to have more than a few peers that have not yet relayed txn.
+    if (a.nLastTXTime != b.nLastTXTime) return a.nLastTXTime < b.nLastTXTime;
+    if (a.fRelayTxes != b.fRelayTxes) return b.fRelayTxes;
+    if (a.fBloomFilter != b.fBloomFilter) return a.fBloomFilter;
+    return a.nTimeConnected > b.nTimeConnected;
+}
 
 /** Try to find a connection to evict when the node is full.
  *  Extreme care must be taken to avoid opening the node to attacker
@@ -887,7 +909,7 @@ static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvict
  *   to forge.  In order to partition a node the attacker must be
  *   simultaneously better at all of them than honest peers.
  */
-static bool AttemptToEvictConnection(bool fPreferNewConnection) {
+static bool AttemptToEvictConnection() {
     std::vector<NodeEvictionCandidate> vEvictionCandidates;
     {
         LOCK(cs_vNodes);
@@ -899,7 +921,9 @@ static bool AttemptToEvictConnection(bool fPreferNewConnection) {
                 continue;
             if (node->fDisconnect)
                 continue;
-            NodeEvictionCandidate candidate = {node->id, node->nTimeConnected, node->nMinPingUsecTime, node->addr, node->nKeyedNetGroup};
+            NodeEvictionCandidate candidate = {node->id, node->nTimeConnected, node->nMinPingUsecTime,
+                                               node->nLastBlockTime, node->nLastTXTime, node->fNetworkNode,
+                                               node->fRelayTxes, node->pfilter != NULL, node->addr, node->nKeyedNetGroup};
             vEvictionCandidates.push_back(candidate);
         }
     }
@@ -922,6 +946,20 @@ static bool AttemptToEvictConnection(bool fPreferNewConnection) {
 
     if (vEvictionCandidates.empty()) return false;
 
+    // Protect 4 nodes that most recently sent us transactions.
+    // An attacker cannot manipulate this metric without performing useful work.
+    std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareNodeTXTime);
+    vEvictionCandidates.erase(vEvictionCandidates.end() - std::min(4, static_cast<int>(vEvictionCandidates.size())), vEvictionCandidates.end());
+
+    if (vEvictionCandidates.empty()) return false;
+
+    // Protect 4 nodes that most recently sent us blocks.
+    // An attacker cannot manipulate this metric without performing useful work.
+    std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareNodeBlockTime);
+    vEvictionCandidates.erase(vEvictionCandidates.end() - std::min(4, static_cast<int>(vEvictionCandidates.size())), vEvictionCandidates.end());
+
+    if (vEvictionCandidates.empty()) return false;
+
     // Protect the half of the remaining nodes which have been connected the longest.
     // This replicates the non-eviction implicit behavior, and precludes attacks that start later.
     std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), ReverseCompareNodeTimeConnected);
@@ -950,13 +988,6 @@ static bool AttemptToEvictConnection(bool fPreferNewConnection) {
     // Reduce to the network group with the most connections
     vEvictionCandidates = std::move(mapAddrCounts[naMostConnections]);
 
-    // Do not disconnect peers if there is only one unprotected connection from their network group.
-    // This step excessively favors netgroup diversity, and should be removed once more protective criteria are established.
-    if (vEvictionCandidates.size() <= 1)
-        // unless we prefer the new connection (for whitelisted peers)
-        if (!fPreferNewConnection)
-            return false;
-
     // Disconnect from the network group with the most connections
     NodeId evicted = vEvictionCandidates.front().id;
     LOCK(cs_vNodes);
@@ -1022,7 +1053,7 @@ static void AcceptConnection(const ListenSocket& hListenSocket) {
 
     if (nInbound >= nMaxInbound)
     {
-        if (!AttemptToEvictConnection(whitelisted)) {
+        if (!AttemptToEvictConnection()) {
             // No connection to evict, disconnect the new connection
             LogPrint("net", "failed to find an eviction candidate - connection dropped (full)\n");
             CloseSocket(hSocket);
@@ -1435,6 +1466,18 @@ void MapPort(bool)
 
 
 
+static std::string GetDNSHost(const CDNSSeedData& data, ServiceFlags* requiredServiceBits)
+{
+    //use default host for non-filter-capable seeds or if we use the default service bits (NODE_NETWORK)
+    if (!data.supportsServiceBitsFiltering || *requiredServiceBits == NODE_NETWORK) {
+        *requiredServiceBits = NODE_NETWORK;
+        return data.host;
+    }
+
+    return strprintf("x%x.%s", *requiredServiceBits, data.host);
+}
+
+
 void ThreadDNSAddressSeed()
 {
     // goal: only query DNS seeds if address need is acute
@@ -1461,7 +1504,7 @@ void ThreadDNSAddressSeed()
             std::vector<CNetAddr> vIPs;
             std::vector<CAddress> vAdd;
             ServiceFlags requiredServiceBits = nRelevantServices;
-            if (LookupHost(seed.getHost(requiredServiceBits).c_str(), vIPs, 0, true))
+            if (LookupHost(GetDNSHost(seed, &requiredServiceBits).c_str(), vIPs, 0, true))
             {
                 BOOST_FOREACH(const CNetAddr& ip, vIPs)
                 {
@@ -2399,6 +2442,8 @@ CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNa
     fSentAddr = false;
     pfilter = new CBloomFilter();
     timeLastMempoolReq = 0;
+    nLastBlockTime = 0;
+    nLastTXTime = 0;
     nPingNonceSent = 0;
     nPingUsecStart = 0;
     nPingUsecTime = 0;
diff --git a/src/net.h b/src/net.h
index 54a86d88dc..67b95fe0e4 100644
--- a/src/net.h
+++ b/src/net.h
@@ -419,6 +419,11 @@ public:
 
     // Last time a "MEMPOOL" request was serviced.
     std::atomic<int64_t> timeLastMempoolReq;
+
+    // Block and TXN accept times
+    std::atomic<int64_t> nLastBlockTime;
+    std::atomic<int64_t> nLastTXTime;
+
     // Ping time measurement:
     // The pong reply we're expecting, or 0 if no pong expected.
     uint64_t nPingNonceSent;
diff --git a/src/qt/forms/receiverequestdialog.ui b/src/qt/forms/receiverequestdialog.ui
index 1e484dd9a0..4163f4189c 100644
--- a/src/qt/forms/receiverequestdialog.ui
+++ b/src/qt/forms/receiverequestdialog.ui
@@ -22,7 +22,7 @@
      <property name="minimumSize">
       <size>
        <width>300</width>
-       <height>300</height>
+       <height>320</height>
       </size>
      </property>
      <property name="toolTip">
diff --git a/src/qt/guiconstants.h b/src/qt/guiconstants.h
index 4b2c10dd48..bab9923d20 100644
--- a/src/qt/guiconstants.h
+++ b/src/qt/guiconstants.h
@@ -43,7 +43,7 @@ static const int TOOLTIP_WRAP_THRESHOLD = 80;
 static const int MAX_URI_LENGTH = 255;
 
 /* QRCodeDialog -- size of exported QR Code image */
-#define EXPORT_IMAGE_SIZE 256
+#define QR_IMAGE_SIZE 300
 
 /* Number of frames in spinner animation */
 #define SPINNER_FRAMES 36
diff --git a/src/qt/receiverequestdialog.cpp b/src/qt/receiverequestdialog.cpp
index a1e9156eea..b13ea3df70 100644
--- a/src/qt/receiverequestdialog.cpp
+++ b/src/qt/receiverequestdialog.cpp
@@ -45,7 +45,7 @@ QImage QRImageWidget::exportImage()
 {
     if(!pixmap())
         return QImage();
-    return pixmap()->toImage().scaled(EXPORT_IMAGE_SIZE, EXPORT_IMAGE_SIZE);
+    return pixmap()->toImage();
 }
 
 void QRImageWidget::mousePressEvent(QMouseEvent *event)
@@ -166,20 +166,32 @@ void ReceiveRequestDialog::update()
                 ui->lblQRCode->setText(tr("Error encoding URI into QR Code."));
                 return;
             }
-            QImage myImage = QImage(code->width + 8, code->width + 8, QImage::Format_RGB32);
-            myImage.fill(0xffffff);
+            QImage qrImage = QImage(code->width + 8, code->width + 8, QImage::Format_RGB32);
+            qrImage.fill(0xffffff);
             unsigned char *p = code->data;
             for (int y = 0; y < code->width; y++)
             {
                 for (int x = 0; x < code->width; x++)
                 {
-                    myImage.setPixel(x + 4, y + 4, ((*p & 1) ? 0x0 : 0xffffff));
+                    qrImage.setPixel(x + 4, y + 4, ((*p & 1) ? 0x0 : 0xffffff));
                     p++;
                 }
             }
             QRcode_free(code);
 
-            ui->lblQRCode->setPixmap(QPixmap::fromImage(myImage).scaled(300, 300));
+            QImage qrAddrImage = QImage(QR_IMAGE_SIZE, QR_IMAGE_SIZE+20, QImage::Format_RGB32);
+            qrAddrImage.fill(0xffffff);
+            QPainter painter(&qrAddrImage);
+            painter.drawImage(0, 0, qrImage.scaled(QR_IMAGE_SIZE, QR_IMAGE_SIZE));
+            QFont font = GUIUtil::fixedPitchFont();
+            font.setPixelSize(12);
+            painter.setFont(font);
+            QRect paddedRect = qrAddrImage.rect();
+            paddedRect.setHeight(QR_IMAGE_SIZE+12);
+            painter.drawText(paddedRect, Qt::AlignBottom|Qt::AlignCenter, info.address);
+            painter.end();
+
+            ui->lblQRCode->setPixmap(QPixmap::fromImage(qrAddrImage));
             ui->btnSaveAs->setEnabled(true);
         }
     }
diff --git a/src/qt/receiverequestdialog.h b/src/qt/receiverequestdialog.h
index 4cab4caff1..676745a858 100644
--- a/src/qt/receiverequestdialog.h
+++ b/src/qt/receiverequestdialog.h
@@ -10,6 +10,7 @@
 #include <QDialog>
 #include <QImage>
 #include <QLabel>
+#include <QPainter>
 
 class OptionsModel;
 
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 992914f88c..9723e394d6 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -388,8 +388,13 @@ UniValue createrawtransaction(const UniValue& params, bool fHelp)
 
         // set the sequence number if passed in the parameters object
         const UniValue& sequenceObj = find_value(o, "sequence");
-        if (sequenceObj.isNum())
-            nSequence = sequenceObj.get_int();
+        if (sequenceObj.isNum()) {
+            int64_t seqNr64 = sequenceObj.get_int64();
+            if (seqNr64 < 0 || seqNr64 > std::numeric_limits<uint32_t>::max())
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, sequence number is out of range");
+            else
+                nSequence = (uint32_t)seqNr64;
+        }
 
         CTxIn in(COutPoint(txid, nOutput), CScript(), nSequence);
 
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 9faf21591f..723b2eceff 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -42,6 +42,7 @@ bool bSpendZeroConfChange = DEFAULT_SPEND_ZEROCONF_CHANGE;
 bool fSendFreeTransactions = DEFAULT_SEND_FREE_TRANSACTIONS;
 
 const char * DEFAULT_WALLET_DAT = "wallet.dat";
+const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
 /**
  * Fees smaller than this (in satoshi) are considered zero fee (for transaction creation)
@@ -91,7 +92,51 @@ CPubKey CWallet::GenerateNewKey()
     bool fCompressed = CanSupportFeature(FEATURE_COMPRPUBKEY); // default to compressed public keys if we want 0.6.0 wallets
 
     CKey secret;
-    secret.MakeNewKey(fCompressed);
+
+    // Create new metadata
+    int64_t nCreationTime = GetTime();
+    CKeyMetadata metadata(nCreationTime);
+
+    // use HD key derivation if HD was enabled during wallet creation
+    if (!hdChain.masterKeyID.IsNull()) {
+        // for now we use a fixed keypath scheme of m/0'/0'/k
+        CKey key;                      //master key seed (256bit)
+        CExtKey masterKey;             //hd master key
+        CExtKey accountKey;            //key at m/0'
+        CExtKey externalChainChildKey; //key at m/0'/0'
+        CExtKey childKey;              //key at m/0'/0'/<n>'
+
+        // try to get the master key
+        if (!GetKey(hdChain.masterKeyID, key))
+            throw std::runtime_error("CWallet::GenerateNewKey(): Master key not found");
+
+        masterKey.SetMaster(key.begin(), key.size());
+
+        // derive m/0'
+        // use hardened derivation (child keys >= 0x80000000 are hardened after bip32)
+        masterKey.Derive(accountKey, BIP32_HARDENED_KEY_LIMIT);
+
+        // derive m/0'/0'
+        accountKey.Derive(externalChainChildKey, BIP32_HARDENED_KEY_LIMIT);
+
+        // derive child key at next index, skip keys already known to the wallet
+        do
+        {
+            // always derive hardened keys
+            // childIndex | BIP32_HARDENED_KEY_LIMIT = derive childIndex in hardened child-index-range
+            // example: 1 | BIP32_HARDENED_KEY_LIMIT == 0x80000001 == 2147483649
+            externalChainChildKey.Derive(childKey, hdChain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
+            // increment childkey index
+            hdChain.nExternalChainCounter++;
+        } while(HaveKey(childKey.key.GetPubKey().GetID()));
+        secret = childKey.key;
+
+        // update the chain model in the database
+        if (!CWalletDB(strWalletFile).WriteHDChain(hdChain))
+            throw std::runtime_error("CWallet::GenerateNewKey(): Writing HD chain model failed");
+    } else {
+        secret.MakeNewKey(fCompressed);
+    }
 
     // Compressed public keys were introduced in version 0.6.0
     if (fCompressed)
@@ -100,9 +145,7 @@ CPubKey CWallet::GenerateNewKey()
     CPubKey pubkey = secret.GetPubKey();
     assert(secret.VerifyPubKey(pubkey));
 
-    // Create new metadata
-    int64_t nCreationTime = GetTime();
-    mapKeyMetadata[pubkey.GetID()] = CKeyMetadata(nCreationTime);
+    mapKeyMetadata[pubkey.GetID()] = metadata;
     if (!nTimeFirstKey || nCreationTime < nTimeFirstKey)
         nTimeFirstKey = nCreationTime;
 
@@ -1121,6 +1164,37 @@ CAmount CWallet::GetChange(const CTransaction& tx) const
     return nChange;
 }
 
+bool CWallet::SetHDMasterKey(const CKey& key)
+{
+    LOCK(cs_wallet);
+
+    // store the key as normal "key"/"ckey" object
+    // in the database
+    // key metadata is not required
+    CPubKey pubkey = key.GetPubKey();
+    if (!AddKeyPubKey(key, pubkey))
+        throw std::runtime_error("CWallet::GenerateNewKey(): AddKey failed");
+
+    // store the keyid (hash160) together with
+    // the child index counter in the database
+    // as a hdchain object
+    CHDChain newHdChain;
+    newHdChain.masterKeyID = pubkey.GetID();
+    SetHDChain(newHdChain, false);
+
+    return true;
+}
+
+bool CWallet::SetHDChain(const CHDChain& chain, bool memonly)
+{
+    LOCK(cs_wallet);
+    if (!memonly && !CWalletDB(strWalletFile).WriteHDChain(chain))
+        throw runtime_error("AddHDChain(): writing chain failed");
+
+    hdChain = chain;
+    return true;
+}
+
 int64_t CWalletTx::GetTxTime() const
 {
     int64_t n = nTimeSmart;
@@ -3135,6 +3209,7 @@ std::string CWallet::GetWalletHelpString(bool showDebug)
         strUsage += HelpMessageOpt("-sendfreetransactions", strprintf(_("Send transactions as zero-fee transactions if possible (default: %u)"), DEFAULT_SEND_FREE_TRANSACTIONS));
     strUsage += HelpMessageOpt("-spendzeroconfchange", strprintf(_("Spend unconfirmed change when sending transactions (default: %u)"), DEFAULT_SPEND_ZEROCONF_CHANGE));
     strUsage += HelpMessageOpt("-txconfirmtarget=<n>", strprintf(_("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)"), DEFAULT_TX_CONFIRM_TARGET));
+    strUsage += HelpMessageOpt("-usehd", _("Use hierarchical deterministic key generation (HD) after bip32. Only has effect during wallet creation/first start") + " " + strprintf(_("(default: %u)"), DEFAULT_USE_HD_WALLET));
     strUsage += HelpMessageOpt("-upgradewallet", _("Upgrade wallet to latest format on startup"));
     strUsage += HelpMessageOpt("-wallet=<file>", _("Specify wallet file (within data directory)") + " " + strprintf(_("(default: %s)"), DEFAULT_WALLET_DAT));
     strUsage += HelpMessageOpt("-walletbroadcast", _("Make the wallet broadcast transactions") + " " + strprintf(_("(default: %u)"), DEFAULT_WALLETBROADCAST));
@@ -3222,6 +3297,13 @@ bool CWallet::InitLoadWallet()
     if (fFirstRun)
     {
         // Create new keyUser and set as default key
+        if (GetBoolArg("-usehd", DEFAULT_USE_HD_WALLET)) {
+            // generate a new master key
+            CKey key;
+            key.MakeNewKey(true);
+            if (!walletInstance->SetHDMasterKey(key))
+                throw std::runtime_error("CWallet::GenerateNewKey(): Storing master key failed");
+        }
         CPubKey newDefaultKey;
         if (walletInstance->GetKeyFromPool(newDefaultKey)) {
             walletInstance->SetDefaultKey(newDefaultKey);
@@ -3231,6 +3313,13 @@ bool CWallet::InitLoadWallet()
 
         walletInstance->SetBestChain(chainActive.GetLocator());
     }
+    else if (mapArgs.count("-usehd")) {
+        bool useHD = GetBoolArg("-usehd", DEFAULT_USE_HD_WALLET);
+        if (!walletInstance->hdChain.masterKeyID.IsNull() && !useHD)
+            return InitError(strprintf(_("Error loading %s: You can't disable HD on a already existing HD wallet"), walletFile));
+        if (walletInstance->hdChain.masterKeyID.IsNull() && useHD)
+            return InitError(strprintf(_("Error loading %s: You can't enable HD on a already existing non-HD wallet"), walletFile));
+    }
 
     LogPrintf(" wallet      %15dms\n", GetTimeMillis() - nStart);
 
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 683c901444..7fc6ce5de5 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -57,6 +57,9 @@ static const unsigned int DEFAULT_TX_CONFIRM_TARGET = 2;
 static const unsigned int MAX_FREE_TRANSACTION_CREATE_SIZE = 1000;
 static const bool DEFAULT_WALLETBROADCAST = true;
 
+//! if set, all keys will be derived by using BIP32
+static const bool DEFAULT_USE_HD_WALLET = true;
+
 extern const char * DEFAULT_WALLET_DAT;
 
 class CBlockIndex;
@@ -574,6 +577,9 @@ private:
 
     void SyncMetaData(std::pair<TxSpends::iterator, TxSpends::iterator>);
 
+    /* the hd chain data model (external chain counters) */
+    CHDChain hdChain;
+
 public:
     /*
      * Main wallet lock.
@@ -889,6 +895,12 @@ public:
     static bool ParameterInteraction();
 
     bool BackupWallet(const std::string& strDest);
+
+    /* Set the hd chain model (chain child index counters) */
+    bool SetHDChain(const CHDChain& chain, bool memonly);
+
+    /* Set the current hd master key (will reset the chain child index counters) */
+    bool SetHDMasterKey(const CKey& key);
 };
 
 /** A key allocated from the key pool. */
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index b5037c9a65..7bfd490950 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -599,6 +599,16 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
                 return false;
             }
         }
+        else if (strType == "hdchain")
+        {
+            CHDChain chain;
+            ssValue >> chain;
+            if (!pwallet->SetHDChain(chain, true))
+            {
+                strErr = "Error reading wallet database: SetHDChain failed";
+                return false;
+            }
+        }
     } catch (...)
     {
         return false;
@@ -1003,3 +1013,10 @@ bool CWalletDB::EraseDestData(const std::string &address, const std::string &key
     nWalletDBUpdated++;
     return Erase(std::make_pair(std::string("destdata"), std::make_pair(address, key)));
 }
+
+
+bool CWalletDB::WriteHDChain(const CHDChain& chain)
+{
+    nWalletDBUpdated++;
+    return Write(std::string("hdchain"), chain);
+}
diff --git a/src/wallet/walletdb.h b/src/wallet/walletdb.h
index 00c10ea70f..71b0ff26db 100644
--- a/src/wallet/walletdb.h
+++ b/src/wallet/walletdb.h
@@ -40,6 +40,35 @@ enum DBErrors
     DB_NEED_REWRITE
 };
 
+/* simple hd chain data model */
+class CHDChain
+{
+public:
+    uint32_t nExternalChainCounter;
+    CKeyID masterKeyID; //!< master key hash160
+
+    static const int CURRENT_VERSION = 1;
+    int nVersion;
+
+    CHDChain() { SetNull(); }
+    ADD_SERIALIZE_METHODS;
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion)
+    {
+        READWRITE(this->nVersion);
+        nVersion = this->nVersion;
+        READWRITE(nExternalChainCounter);
+        READWRITE(masterKeyID);
+    }
+
+    void SetNull()
+    {
+        nVersion = CHDChain::CURRENT_VERSION;
+        nExternalChainCounter = 0;
+        masterKeyID.SetNull();
+    }
+};
+
 class CKeyMetadata
 {
 public:
@@ -134,6 +163,9 @@ public:
     static bool Recover(CDBEnv& dbenv, const std::string& filename, bool fOnlyKeys);
     static bool Recover(CDBEnv& dbenv, const std::string& filename);
 
+    //! write the hdchain model (external chain child index counter)
+    bool WriteHDChain(const CHDChain& chain);
+
 private:
     CWalletDB(const CWalletDB&);
     void operator=(const CWalletDB&);