diff --git a/depends/Makefile b/depends/Makefile
index ba5051d22..2d005ed84 100644
--- a/depends/Makefile
+++ b/depends/Makefile
@@ -1,221 +1,225 @@
 .NOTPARALLEL :
 
 SOURCES_PATH ?= $(BASEDIR)/sources
 WORK_PATH = $(BASEDIR)/work
 BASE_CACHE ?= $(BASEDIR)/built
 SDK_PATH ?= $(BASEDIR)/SDKs
 NO_QT ?=
+NO_PROTOBUF ?=
 RAPIDCHECK ?=
 NO_WALLET ?=
 NO_ZMQ ?=
 NO_UPNP ?=
 FALLBACK_DOWNLOAD_PATH ?= https://download.bitcoinabc.org/depends-sources
 
 BUILD = $(shell ./config.guess)
 HOST ?= $(BUILD)
 PATCHES_PATH = $(BASEDIR)/patches
 BASEDIR = $(CURDIR)
 HASH_LENGTH:=11
 DOWNLOAD_CONNECT_TIMEOUT:=30
 DOWNLOAD_RETRIES:=3
 HOST_ID_SALT ?= salt
 BUILD_ID_SALT ?= salt
 JOBS ?= $(shell echo $$(($(shell nproc 2> /dev/null || sysctl -n hw.ncpu 2> /dev/null || echo 0) + 1)))
 
 host:=$(BUILD)
 ifneq ($(HOST),)
 host:=$(HOST)
 host_toolchain:=$(HOST)-
 endif
 
 ifneq ($(DEBUG),)
 release_type=debug
 else
 release_type=release
 endif
 
 base_build_dir=$(WORK_PATH)/build
 base_staging_dir=$(WORK_PATH)/staging
 base_download_dir=$(WORK_PATH)/download
 canonical_host:=$(shell ./config.sub $(HOST))
 build:=$(shell ./config.sub $(BUILD))
 
 build_arch =$(firstword $(subst -, ,$(build)))
 build_vendor=$(word 2,$(subst -, ,$(build)))
 full_build_os:=$(subst $(build_arch)-$(build_vendor)-,,$(build))
 build_os:=$(findstring linux,$(full_build_os))
 build_os+=$(findstring darwin,$(full_build_os))
 build_os:=$(strip $(build_os))
 ifeq ($(build_os),)
 build_os=$(full_build_os)
 endif
 
 host_arch=$(firstword $(subst -, ,$(canonical_host)))
 host_vendor=$(word 2,$(subst -, ,$(canonical_host)))
 full_host_os:=$(subst $(host_arch)-$(host_vendor)-,,$(canonical_host))
 host_os:=$(findstring linux,$(full_host_os))
 host_os+=$(findstring darwin,$(full_host_os))
 host_os+=$(findstring mingw32,$(full_host_os))
 host_os:=$(strip $(host_os))
 ifeq ($(host_os),)
 host_os=$(full_host_os)
 endif
 
 $(host_arch)_$(host_os)_prefix=$(BASEDIR)/$(host)
 $(host_arch)_$(host_os)_host=$(host)
 host_prefix=$($(host_arch)_$(host_os)_prefix)
 build_prefix=$(host_prefix)/native
 build_host=$(build)
 
 AT_$(V):=
 AT_:=@
 AT:=$(AT_$(V))
 
 all: install
 
 include hosts/$(host_os).mk
 include hosts/default.mk
 include builders/$(build_os).mk
 include builders/default.mk
 include packages/packages.mk
 
 build_id_string:=$(BUILD_ID_SALT)
 build_id_string+=$(shell $(build_CC) --version 2>/dev/null)
 build_id_string+=$(shell $(build_AR) --version 2>/dev/null)
 build_id_string+=$(shell $(build_CXX) --version 2>/dev/null)
 build_id_string+=$(shell $(build_RANLIB) --version 2>/dev/null)
 build_id_string+=$(shell $(build_STRIP) --version 2>/dev/null)
 
 $(host_arch)_$(host_os)_id_string:=$(HOST_ID_SALT)
 $(host_arch)_$(host_os)_id_string+=$(shell $(host_CC) --version 2>/dev/null)
 $(host_arch)_$(host_os)_id_string+=$(shell $(host_AR) --version 2>/dev/null)
 $(host_arch)_$(host_os)_id_string+=$(shell $(host_CXX) --version 2>/dev/null)
 $(host_arch)_$(host_os)_id_string+=$(shell $(host_RANLIB) --version 2>/dev/null)
 $(host_arch)_$(host_os)_id_string+=$(shell $(host_STRIP) --version 2>/dev/null)
 
 qt_packages_$(NO_QT) = $(qt_packages) $(qt_$(host_os)_packages) $(qt_$(host_arch)_$(host_os)_packages)
 wallet_packages_$(NO_WALLET) = $(wallet_packages)
 upnp_packages_$(NO_UPNP) = $(upnp_packages)
 zmq_packages_$(NO_ZMQ) = $(zmq_packages)
 
+protobuf_packages_$(NO_PROTOBUF) = $(protobuf_packages)
 rapidcheck_packages_$(RAPIDCHECK) = $(rapidcheck_packages)
 
 packages += $($(host_arch)_$(host_os)_packages) $($(host_os)_packages) $(qt_packages_) $(wallet_packages_) $(upnp_packages_)
 native_packages += $($(host_arch)_$(host_os)_native_packages) $($(host_os)_native_packages)
 
-ifneq ($(qt_packages_),)
-native_packages += $(qt_native_packages)
+ifneq ($(protobuf_packages_),)
+native_packages += $(protobuf_native_packages)
+packages += $(protobuf_packages)
 endif
 
 ifneq ($(zmq_packages_),)
 packages += $(zmq_packages)
 endif
 
 ifeq ($(rapidcheck_packages_),)
 packages += $(rapidcheck_packages)
 endif
 
 all_packages = $(packages) $(native_packages)
 
 meta_depends = Makefile funcs.mk builders/default.mk hosts/default.mk hosts/$(host_os).mk builders/$(build_os).mk
 
 $(host_arch)_$(host_os)_native_toolchain?=$($(host_os)_native_toolchain)
 
 include funcs.mk
 
 toolchain_path=$($($(host_arch)_$(host_os)_native_toolchain)_prefixbin)
 final_build_id_long+=$(shell $(build_SHA256SUM) config.site.in)
 final_build_id+=$(shell echo -n "$(final_build_id_long)" | $(build_SHA256SUM) | cut -c-$(HASH_LENGTH))
 $(host_prefix)/.stamp_$(final_build_id): $(native_packages) $(packages)
 	$(AT)rm -rf $(@D)
 	$(AT)mkdir -p $(@D)
 	$(AT)echo copying packages: $^
 	$(AT)echo to: $(@D)
 	$(AT)cd $(@D); $(foreach package,$^, tar xf $($(package)_cached); )
 	$(AT)touch $@
 
 $(host_prefix)/share/config.site : config.site.in $(host_prefix)/.stamp_$(final_build_id)
 	$(AT)@mkdir -p $(@D)
 	$(AT)sed -e 's|@HOST@|$(host)|' \
             -e 's|@CC@|$(toolchain_path)$(host_CC)|' \
             -e 's|@CXX@|$(toolchain_path)$(host_CXX)|' \
             -e 's|@AR@|$(toolchain_path)$(host_AR)|' \
             -e 's|@RANLIB@|$(toolchain_path)$(host_RANLIB)|' \
             -e 's|@NM@|$(toolchain_path)$(host_NM)|' \
             -e 's|@STRIP@|$(toolchain_path)$(host_STRIP)|' \
             -e 's|@build_os@|$(build_os)|' \
             -e 's|@host_os@|$(host_os)|' \
             -e 's|@CFLAGS@|$(strip $(host_CFLAGS) $(host_$(release_type)_CFLAGS))|' \
             -e 's|@CXXFLAGS@|$(strip $(host_CXXFLAGS) $(host_$(release_type)_CXXFLAGS))|' \
             -e 's|@CPPFLAGS@|$(strip $(host_CPPFLAGS) $(host_$(release_type)_CPPFLAGS))|' \
             -e 's|@LDFLAGS@|$(strip $(host_LDFLAGS) $(host_$(release_type)_LDFLAGS))|' \
             -e 's|@no_qt@|$(NO_QT)|' \
             -e 's|@no_zmq@|$(NO_ZMQ)|' \
+            -e 's|@no_bip70@|$(NO_PROTOBUF)|' \
             -e 's|@no_wallet@|$(NO_WALLET)|' \
             -e 's|@no_upnp@|$(NO_UPNP)|' \
             -e 's|@debug@|$(DEBUG)|' \
             $< > $@
 	$(AT)touch $@
 
 
 define check_or_remove_cached
   mkdir -p $(BASE_CACHE)/$(host)/$(package) && cd $(BASE_CACHE)/$(host)/$(package); \
   $(build_SHA256SUM) -c $($(package)_cached_checksum) >/dev/null 2>/dev/null || \
   ( rm -f $($(package)_cached_checksum); \
     if test -f "$($(package)_cached)"; then echo "Checksum mismatch for $(package). Forcing rebuild.."; rm -f $($(package)_cached_checksum) $($(package)_cached); fi )
 endef
 
 define check_or_remove_sources
   mkdir -p $($(package)_source_dir); cd $($(package)_source_dir); \
   test -f $($(package)_fetched) && ( $(build_SHA256SUM) -c $($(package)_fetched) >/dev/null 2>/dev/null || \
     ( echo "Checksum missing or mismatched for $(package) source. Forcing re-download."; \
       rm -f $($(package)_all_sources) $($(1)_fetched))) || true
 endef
 
 check-packages:
 	@$(foreach package,$(all_packages),$(call check_or_remove_cached,$(package));)
 check-sources:
 	@$(foreach package,$(all_packages),$(call check_or_remove_sources,$(package));)
 
 $(host_prefix)/share/config.site: check-packages
 
 check-packages: check-sources
 
 clean-all: clean
 	@rm -rf $(SOURCES_PATH) x86_64* i686* arm* aarch64*
 
 clean:
 	@rm -rf $(WORK_PATH) $(BASE_CACHE) $(BUILD)
 
 install: check-packages $(host_prefix)/share/config.site
 
 download-one: check-sources $(all_sources)
 
 download-osx:
 	@$(MAKE) -s HOST=x86_64-apple-darwin16 download-one
 download-linux:
 	@$(MAKE) -s HOST=x86_64-unknown-linux-gnu download-one
 download-win:
 	@$(MAKE) -s HOST=x86_64-w64-mingw32 download-one
 download: download-osx download-linux download-win
 
 build-linux64: download-linux
 	@$(MAKE) -s HOST=x86_64-linux-gnu install
 build-linux32: download-linux
 	@$(MAKE) -s HOST=i686-pc-linux-gnu install
 build-linux-arm: download-linux
 	@$(MAKE) -s HOST=arm-linux-gnueabihf install
 build-linux-aarch64: download-linux
 	@$(MAKE) -s HOST=aarch64-linux-gnu install
 build-osx: download-osx
 	@$(MAKE) -s HOST=x86_64-apple-darwin16 install
 build-win32: download-win
 	@$(MAKE) -s HOST=i686-w64-mingw32 install
 build-win64: download-win
 	@$(MAKE) -s HOST=x86_64-w64-mingw32 install
 
 build-all: build-linux64 build-linux32 build-linux-arm build-linux-aarch64 build-osx build-win32 build-win64
 
 $(foreach package,$(all_packages),$(eval $(call ext_add_stages,$(package))))
 
 .PHONY: install cached clean clean-all download-one download-osx download-linux download-win download check-packages check-sources
diff --git a/depends/README.md b/depends/README.md
index 9ff742951..13a155199 100644
--- a/depends/README.md
+++ b/depends/README.md
@@ -1,115 +1,116 @@
 ### Usage
 
 To build dependencies for the current arch+OS:
 
     make
 
 To build for another arch/OS:
 
     make build-<platform>
 
 Where `<platform>` is one of the following:
  - linux64
  - linux32
  - linux-arm
  - linux-aarch64
  - osx
  - win64
 
 For example, building the dependencies for macOS:
 
     make build-osx
 
 Note that it will use all the CPU cores available on the machine by default.
 This behavior can be changed by setting the `JOBS` environment variable (see
 below).
 
 To use the dependencies for building Bitcoin ABC, you need to set the platform
 file to be used by `cmake`.
 The platform files are located under `cmake/platforms/`.
 For example, cross-building for macOS (run from the project root):
 
     mkdir build_osx
     cd build_osx
     cmake -GNinja .. -DCMAKE_TOOLCHAIN_FILE=../cmake/platforms/OSX.cmake
     ninja
 
 No other options are needed, the paths are automatically configured.
 
 ### Install the required dependencies: Ubuntu & Debian
 
 #### Common to all arch/OS
 
     sudo apt-get install build-essential autoconf automake cmake curl git libtool ninja-build patch pkg-config python3
 
 #### For macOS cross compilation
 
     sudo apt-get install imagemagick libbz2-dev libcap-dev librsvg2-bin libtiff-tools python3-setuptools
 
 #### For Win64 cross compilation
 
 - see [build-windows.md](../doc/build-windows.md#cross-compilation-for-ubuntu-and-windows-subsystem-for-linux)
 
 #### For linux cross compilation
 
 Common linux dependencies:
 
     sudo apt-get install gperf
 
 For linux 32 bits cross compilation:
 
 First add the i386 architecture to `dpkg`:
 
     sudo dpkg --add-architecture i386
     sudo apt-get update
 
 Then install the dependencies:
 
     sudo apt-get install lib32stdc++-8-dev libc6-dev:i386
 
 For linux ARM cross compilation:
 
     sudo apt-get install g++-arm-linux-gnueabihf
 
 For linux AARCH64 cross compilation:
 
     sudo apt-get install g++-aarch64-linux-gnu
 
 
 ### Dependency Options
 
 The following can be set when running make: make FOO=bar
 
     SOURCES_PATH: downloaded sources will be placed here
     BASE_CACHE: built packages will be placed here
     SDK_PATH: Path where sdk's can be found (used by macOS)
     FALLBACK_DOWNLOAD_PATH: If a source file can't be fetched, try here before giving up
     NO_QT: Don't download/build/cache qt and its dependencies
     NO_ZMQ: Don't download/build/cache packages needed for enabling zeromq
     NO_WALLET: Don't download/build/cache libs needed to enable the wallet
     NO_UPNP: Don't download/build/cache packages needed for enabling upnp
     DEBUG: disable some optimizations and enable more runtime checking
     RAPIDCHECK: build rapidcheck (experimental, requires cmake)
+    NO_PROTOBUF: Don't download/build/cache protobuf (used for BIP70 support)
     HOST_ID_SALT: Optional salt to use when generating host package ids
     BUILD_ID_SALT: Optional salt to use when generating build package ids
     JOBS: Number of jobs to use for each package build
 
 If some packages are not built, for example by building the depends with
 `make NO_WALLET=1`, the appropriate options should be set when building Bitcoin
 ABC using these dependencies.
 In this example, `-DBUILD_BITCOIN_WALLET=OFF` should be passed to the `cmake`
 command line to ensure that the build will not fail due to missing dependencies.
 
 Additional targets:
 
     download: run 'make download' to fetch all sources without building them
     download-osx: run 'make download-osx' to fetch all sources needed for macOS builds
     download-win: run 'make download-win' to fetch all sources needed for win builds
     download-linux: run 'make download-linux' to fetch all sources needed for linux builds
     build-all: build the dependencies for all the arch/OS
 
 ### Other documentation
 
 - [description.md](description.md): General description of the depends system
 - [packages.md](packages.md): Steps for adding packages
 
diff --git a/depends/config.site.in b/depends/config.site.in
index 3593ec9c5..121e3a64e 100644
--- a/depends/config.site.in
+++ b/depends/config.site.in
@@ -1,102 +1,106 @@
 depends_prefix=$(cd `dirname ${ac_site_file}`/..; pwd -P)
 
 cross_compiling=maybe
 host_alias=@HOST@
 ac_tool_prefix=${host_alias}-
 
 if test -z $with_boost; then
   with_boost=$depends_prefix
 fi
 if test -z $with_qt_plugindir; then
   with_qt_plugindir=$depends_prefix/plugins
 fi
 if test -z $with_qt_translationdir; then
   with_qt_translationdir=$depends_prefix/translations
 fi
 if test -z $with_qt_bindir; then
   with_qt_bindir=$depends_prefix/native/bin
 fi
 if test -z $with_protoc_bindir; then
   with_protoc_bindir=$depends_prefix/native/bin
 fi
 
 
 if test -z $enable_wallet && test -n "@no_wallet@"; then
   enable_wallet=no
 fi
 
 if test -z $with_miniupnpc && test -n "@no_upnp@"; then
   with_miniupnpc=no
 fi
 
 if test -z $with_gui && test -n "@no_qt@"; then
   with_gui=no
 fi
 
 if test -z $enable_zmq && test -n "@no_zmq@"; then
   enable_zmq=no
 fi
 
+if test -z $enable_bip70 && test -n "@no_bip70@"; then
+  enable_bip70=no
+fi
+
 if test x@host_os@ = xdarwin; then
   BREW=no
   PORT=no
 fi
 
 if test x@host_os@ = xmingw32; then
   if test -z $with_qt_incdir; then
     with_qt_incdir=$depends_prefix/include
   fi
   if test -z $with_qt_libdir; then
     with_qt_libdir=$depends_prefix/lib
   fi
 fi
 
 PATH=$depends_prefix/native/bin:$PATH
 PKG_CONFIG="`which pkg-config` --static"
 
 # These two need to remain exported because pkg-config does not see them
 # otherwise. That means they must be unexported at the end of configure.ac to
 # avoid ruining the cache. Sigh.
 
 export PKG_CONFIG_LIBDIR=$depends_prefix/lib/pkgconfig
 export PKG_CONFIG_PATH=$depends_prefix/share/pkgconfig
 
 CPPFLAGS="-I$depends_prefix/include/ $CPPFLAGS"
 LDFLAGS="-L$depends_prefix/lib $LDFLAGS"
 
 CC="@CC@"
 CXX="@CXX@"
 OBJC="${CC}"
 PYTHONPATH=$depends_prefix/native/lib/python3/dist-packages:$PYTHONPATH
 
 if test -n "@AR@"; then
   AR=@AR@
   ac_cv_path_ac_pt_AR=${AR}
 fi
 
 if test -n "@RANLIB@"; then
   RANLIB=@RANLIB@
   ac_cv_path_ac_pt_RANLIB=${RANLIB}
 fi
 
 if test -n "@NM@"; then
   NM=@NM@
   ac_cv_path_ac_pt_NM=${NM}
 fi
 
 if test -n "@debug@"; then
   enable_reduce_exports=no
 fi
 
 if test -n "@CFLAGS@"; then
   CFLAGS="@CFLAGS@ $CFLAGS"
 fi
 if test -n "@CXXFLAGS@"; then
   CXXFLAGS="@CXXFLAGS@ $CXXFLAGS"
 fi
 if test -n "@CPPFLAGS@"; then
   CPPFLAGS="@CPPFLAGS@ $CPPFLAGS"
 fi
 if test -n "@LDFLAGS@"; then
   LDFLAGS="@LDFLAGS@ $LDFLAGS"
 fi
diff --git a/depends/packages/packages.mk b/depends/packages/packages.mk
index 9edcd1eb3..667fde527 100644
--- a/depends/packages/packages.mk
+++ b/depends/packages/packages.mk
@@ -1,23 +1,25 @@
 packages:=boost openssl libevent
 
-qt_native_packages = native_protobuf
-qt_packages = qrencode protobuf zlib
+protobuf_native_packages = native_protobuf
+protobuf_packages = protobuf
+
+qt_packages = qrencode zlib
 
 qt_linux_packages:=qt expat libxcb xcb_proto libXau xproto freetype fontconfig
 
 rapidcheck_packages = rapidcheck
 
 qt_darwin_packages=qt
 qt_mingw32_packages=qt
 
 wallet_packages=bdb
 
 zmq_packages=zeromq
 
 upnp_packages=miniupnpc
 
 darwin_native_packages = native_biplist native_ds_store native_mac_alias
 
 ifneq ($(build_os),darwin)
 darwin_native_packages += native_cctools native_cdrkit native_libdmg-hfsplus
 endif
diff --git a/doc/build-unix.md b/doc/build-unix.md
index 777705163..efb080376 100644
--- a/doc/build-unix.md
+++ b/doc/build-unix.md
@@ -1,257 +1,257 @@
 UNIX BUILD NOTES
 ====================
 Some notes on how to build Bitcoin ABC in Unix.
 
 (For FreeBSD specific instructions, see `build-freebsd.md` in this directory.)
 
 To Build
 ---------------------
 
 Before you start building, please make sure that your compiler supports C++14.
 
 It is recommended to create a build directory to build out-of-tree.
 
 ```bash
 mkdir build
 cd build
 cmake -GNinja ..
 ninja
 ninja install # optional
 ```
 
 This will build bitcoin-qt as well.
 
 Dependencies
 ---------------------
 
 These dependencies are required:
 
  Library     | Purpose          | Description
  ------------|------------------|----------------------
  libssl      | Crypto           | Random Number Generation, Elliptic Curve Cryptography
  libboost    | Utility          | Library for threading, data structures, etc
  libevent    | Networking       | OS independent asynchronous networking
 
 Optional dependencies:
 
  Library     | Purpose          | Description
  ------------|------------------|----------------------
  miniupnpc   | UPnP Support     | Firewall-jumping support
  libdb       | Berkeley DB      | Wallet storage (only needed when wallet enabled)
  qt          | GUI              | GUI toolkit (only needed when GUI enabled)
- protobuf    | Payments in GUI  | Data interchange format used for payment protocol (only needed when GUI enabled)
+ protobuf    | Payments in GUI  | Data interchange format used for payment protocol (only needed when BIP70 enabled)
  libqrencode | QR codes in GUI  | Optional for generating QR codes (only needed when GUI enabled)
  univalue    | Utility          | JSON parsing and encoding (bundled version will be used unless --with-system-univalue passed to configure)
  libzmq3     | ZMQ notification | Optional, allows generating ZMQ notifications (requires ZMQ version >= 4.1.5)
 
 For the versions used, see [dependencies.md](dependencies.md)
 
 Memory Requirements
 --------------------
 
 C++ compilers are memory-hungry. It is recommended to have at least 1.5 GB of
 memory available when compiling Bitcoin ABC. On systems with less, gcc can be
 tuned to conserve memory with additional CXXFLAGS:
 
     cmake -GNinja .. -DCXXFLAGS="--param ggc-min-expand=1 --param ggc-min-heapsize=32768"
 
 Dependency Build Instructions: Ubuntu & Debian
 ----------------------------------------------
 Build requirements:
 
     sudo apt-get install bsdmainutils build-essential libssl-dev libevent-dev ninja-build python3
 
 On Debian Buster (10) or Ubuntu 19.04 and later:
 
     sudo apt-get install cmake
 
 On previous Ubuntu versions, the `cmake` package is too old and needs to be installed from the Kitware APT repository:
 
     sudo apt-get install apt-transport-https ca-certificates gnupg software-properties-common wget
     wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | sudo apt-key add -
 
 Add the repository corresponding to your version (see [instructions from Kitware](https://apt.kitware.com)). For Ubuntu Bionic (18.04):
 
     sudo apt-add-repository 'deb https://apt.kitware.com/ubuntu/ bionic main'
 
 Then update the package list and install `cmake`:
 
     sudo apt update
     sudo apt install cmake
 
 Now, you can either build from self-compiled [depends](/depends/README.md) or
 install the required dependencies with the following instructions.
 
 Options when installing required Boost library files:
 
 1. On at least Ubuntu 16.04+ and Debian 9+ there are generic names for the
 individual boost development packages, so the following can be used to only
 install necessary parts of boost:
 
         sudo apt-get install libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-test-dev libboost-thread-dev
 
 2. If that doesn't work, you can install all boost development packages with:
 
         sudo apt-get install libboost-all-dev
 
 BerkeleyDB 5.3 or later is required for the wallet. This can be installed with:
 
         sudo apt-get install libdb-dev libdb++-dev
 
 See the section "Disable-wallet mode" to build Bitcoin ABC without wallet.
 
 Minipupnc dependencies (can be disabled by passing `-DENABLE_UPNP=OFF` on the cmake command line):
 
     sudo apt-get install libminiupnpc-dev
 
 ZMQ dependencies (provides ZMQ API, can be disabled by passing `-BUILD_BITCOIN_ZMQ=OFF` on the cmake command line):
 
     sudo apt-get install libzmq3-dev
 
 Dependencies for the GUI: Ubuntu & Debian
 -----------------------------------------
 
 If you want to build bitcoin-qt, make sure that the required packages for Qt development
 are installed. Qt 5 is necessary to build the GUI.
 To build without GUI pass `-DBUILD_BITCOIN_QT=OFF` on the cmake command line.
 
 To build with Qt 5 you need the following:
 
     sudo apt-get install libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libprotobuf-dev protobuf-compiler
 
 libqrencode dependencies (can be disabled by passing `-DENABLE_QRCODE=OFF` on the cmake command line):
 
     sudo apt-get install libqrencode-dev
 
 Dependency Build Instructions: Fedora
 -------------------------------------
 Build requirements:
 
     sudo dnf install boost-devel cmake gcc-c++ libdb-cxx-devel libdb-devel libevent-devel ninja-build openssl-devel python3
 
 Minipupnc dependencies (can be disabled by passing `-DENABLE_UPNP=OFF` on the cmake command line):
 
     sudo dnf install miniupnpc-devel
 
 ZMQ dependencies (can be disabled by passing `-BUILD_BITCOIN_ZMQ=OFF` on the cmake command line):
 
     sudo dnf install zeromq-devel
 
 To build with Qt 5 you need the following:
 
     sudo dnf install qt5-qttools-devel qt5-qtbase-devel protobuf-devel
 
 libqrencode dependencies (can be disabled by passing `-DENABLE_QRCODE=OFF`):
 
     sudo dnf install qrencode-devel
 
 Notes
 -----
 The release is built with GCC and then "strip bitcoind" to strip the debug
 symbols, which reduces the executable size by about 90%.
 
 
 miniupnpc
 ---------
 
 [miniupnpc](http://miniupnp.free.fr/) may be used for UPnP port mapping.  It can be downloaded from [here](
 http://miniupnp.tuxfamily.org/files/).  UPnP support is compiled in and
 turned off by default.  See the cmake options for upnp behavior desired:
 
     ENABLE_UPNP            Enable UPnP support (miniupnp required, default ON)
     START_WITH_UPNP        UPnP support turned on by default at runtime (default OFF)
 
 Boost
 -----
 For documentation on building Boost look at their official documentation: http://www.boost.org/build/doc/html/bbv2/installation.html
 
 Security
 --------
 To help make your Bitcoin ABC installation more secure by making certain attacks impossible to
 exploit even if a vulnerability is found, binaries are hardened by default.
 This can be disabled by passing `-DENABLE_HARDENING=OFF`.
 
 Hardening enables the following features:
 * _Position Independent Executable_: Build position independent code to take advantage of Address Space Layout Randomization
     offered by some kernels. Attackers who can cause execution of code at an arbitrary memory
     location are thwarted if they don't know where anything useful is located.
     The stack and heap are randomly located by default, but this allows the code section to be
     randomly located as well.
 
     On an AMD64 processor where a library was not compiled with -fPIC, this will cause an error
     such as: "relocation R_X86_64_32 against `......' can not be used when making a shared object;"
 
     To test that you have built PIE executable, install scanelf, part of paxutils, and use:
 
       scanelf -e ./bitcoin
 
     The output should contain:
 
       TYPE
       ET_DYN
 
 * _Non-executable Stack_: If the stack is executable then trivial stack-based buffer overflow exploits are possible if
     vulnerable buffers are found. By default, Bitcoin ABC should be built with a non-executable stack,
     but if one of the libraries it uses asks for an executable stack or someone makes a mistake
     and uses a compiler extension which requires an executable stack, it will silently build an
     executable without the non-executable stack protection.
 
     To verify that the stack is non-executable after compiling use:
 
       scanelf -e ./bitcoin
 
     The output should contain:
 
       STK/REL/PTL
       RW- R-- RW-
 
     The `STK RW-` means that the stack is readable and writeable but not executable.
 
 Disable-wallet mode
 --------------------
 When the intention is to run only a P2P node without a wallet, Bitcoin ABC may be compiled in
 disable-wallet mode by passing `-DBUILD_BITCOIN_WALLET=OFF` on the cmake command line.
 
 Mining is also possible in disable-wallet mode using the `getblocktemplate` RPC call.
 
 Additional cmake options
 --------------------------
 A list of the cmake options and their current value can be displayed.
 From the build subdirectory (see above), run `cmake -LH ..`.
 
 Setup and Build Example: Arch Linux
 -----------------------------------
 This example lists the steps necessary to setup and build a command line only, non-wallet distribution of the latest changes on Arch Linux:
 
     pacman -S boost cmake git libevent ninja python
     git clone https://github.com/Bitcoin-ABC/bitcoin-abc.git
     cd bitcoin-abc/
     mkdir build
     cd build
     cmake -GNinja .. -DBUILD_BITCOIN_WALLET=OFF -DBUILD_BITCOIN_QT=OFF -DENABLE_UPNP=OFF -DBUILD_BITCOIN_ZMQ=OFF
     ninja
 
 
 ARM Cross-compilation
 -------------------
 These steps can be performed on, for example, a Debian VM. The depends system
 will also work on other Linux distributions, however the commands for
 installing the toolchain will be different.
 
 Make sure you install all the build requirements mentioned above.
 Then, install the toolchain and some additional dependencies:
 
     sudo apt-get install autoconf automake curl g++-arm-linux-gnueabihf gcc-arm-linux-gnueabihf gperf pkg-config
 
 To build executables for ARM:
 
     cd depends
     make build-linux-arm
     cd ..
     mkdir build
     cd build
     cmake -GNinja .. -DCMAKE_TOOLCHAIN_FILE=../cmake/platforms/LinuxARM.cmake -DENABLE_GLIBC_BACK_COMPAT=ON -DENABLE_STATIC_LIBSTDCXX=ON
     ninja
 
 
 For further documentation on the depends system see [README.md](../depends/README.md) in the depends directory.