New Features

GUI

The :manual:cmake-gui(1) gained options to control warnings about deprecated functionality.
The :manual:cmake-gui(1) learned an option to set the toolset to be used with VS IDE and Xcode generators, much like the existing -T option to :manual:cmake(1).
The :manual:cmake-gui(1) gained a Regular Expression Explorer which may be used to create and evaluate regular expressions in real-time. The explorer window is available via the Tools menu.

The -Wdev and -Wno-dev :manual:cmake(1) options now also enable and suppress the deprecated warnings output by default.
The suppression of developer warnings as errors can now be controlled with the new -Werror=dev and -Wno-error=dev :manual:cmake(1) options.
The :manual:cmake(1) -E command-line tools copy, copy_if_different, copy_directory, and make_directory learned to support multiple input files or directories.

The :command:cmake_parse_arguments command is now implemented natively. The :module:CMakeParseArguments module remains as an empty placeholder for compatibility.
The :command:install(DIRECTORY) command learned to support :manual:generator expressions <cmake-generator-expressions(7)> in the list of directories.

The :variable:CMAKE_ERROR_DEPRECATED variable can now be set using the -Werror=deprecated and -Wno-error=deprecated :manual:cmake(1) options.
The :variable:CMAKE_WARN_DEPRECATED variable can now be set using the -Wdeprecated and -Wno-deprecated :manual:cmake(1) options.

The :prop_tgt:VS_GLOBAL_<variable> target property is now implemented for VS 2010 and above. Previously it worked only in VS 2008 and below.

The :module:ExternalProject module learned a new GIT_REMOTE_NAME option to control the git clone --origin value.
The :module:FindBoost module now provides imported targets such as Boost::boost and Boost::filesystem.
The :module:FindFLEX module flex_target() command learned a new DEFINES_FILE option to specify a custom output header to be generated.
The :module:FindGTest module now provides imported targets.
The :module:FindGTK2 module, when GTK2_USE_IMPORTED_TARGETS is enabled, now sets GTK2_LIBRARIES to contain the list of imported targets instead of the paths to the libraries. Moreover it now sets a new GTK2_TARGETS variable containing all the targets imported.
The :module:FindOpenMP module learned to support Clang.
The :module:FindOpenSSL module gained a new OPENSSL_MSVC_STATIC_RT option to search for libraries using the MSVC static runtime.
The :module:FindPNG module now provides imported targets.
The :module:FindTIFF module now provides imported targets.
A :module:FindXalanC module was introduced to find the Apache Xalan-C++ XSL transform processing library.
The :module:FindXercesC module now provides imported targets.

Support was added for the ARM Compiler (arm.com) with compiler id ARMCC.
A new platform file for cross-compiling in the Cray Linux Environment to target compute nodes was added. See :ref:Cross Compiling for the Cray Linux Environment <Cray Cross-Compile> for usage details.
The :manual:Compile Features <cmake-compile-features(7)> functionality is now aware of features supported by Clang compilers on Windows (MinGW).
When building for embedded Apple platforms like iOS CMake learned to build and install combined targets which contain both a device and a simulator build. This behavior can be enabled by setting the :prop_tgt:IOS_INSTALL_COMBINED target property.

The :cpack_gen:CPack DragNDrop Generator learned new variable to specify AppleScript file run to customize appearance of DragNDrop installer folder, including background image setting using supplied PNG or multi-resolution TIFF file. See the :variable:CPACK_DMG_DS_STORE_SETUP_SCRIPT and :variable:CPACK_DMG_BACKGROUND_IMAGE variables.
The :cpack_gen:CPack DEB Generator learned to set the optional config file Source field using a monolithic or per-component variable. See :variable:CPACK_DEBIAN_PACKAGE_SOURCE.
The :cpack_gen:CPack DEB Generator learned to set Package, Section and Priority control fields per-component. See variables :variable:CPACK_DEBIAN_<COMPONENT>_PACKAGE_SECTION and :variable:CPACK_DEBIAN_<COMPONENT>_PACKAGE_PRIORITY.
The :cpack_gen:CPack DragNDrop Generator learned to add multi-lingual SLAs to a DMG which is presented to the user when they try to mount the DMG. See the :variable:CPACK_DMG_SLA_LANGUAGES and :variable:CPACK_DMG_SLA_DIR variables for details.
The :cpack_gen:CPack NSIS Generator learned new variables to add bitmaps to the installer. See the :variable:CPACK_NSIS_MUI_WELCOMEFINISHPAGE_BITMAP and :variable:CPACK_NSIS_MUI_UNWELCOMEFINISHPAGE_BITMAP variables.
The :cpack_gen:CPack RPM Generator learned to set Name and Group control fields per-component. See :variable:CPACK_RPM_<component>_PACKAGE_NAME and :variable:CPACK_RPM_<component>_PACKAGE_GROUP.

Warnings about deprecated functionality are now enabled by default. They may be suppressed with -Wno-deprecated or by setting the :variable:CMAKE_WARN_DEPRECATED variable to false.

The :manual:cmake(1) -E time command now properly passes arguments with spaces or special characters through to the child process. This may break scripts that worked around the bug with their own extra quoting or escaping.
The :generator:Xcode generator was fixed to escape backslashes in strings consistently with other generators. Projects that previously worked around the inconsistency with an extra level of backslashes conditioned on the Xcode generator must be updated to remove the workaround for CMake 3.5 and greater.

The :generator:Visual Studio 14 2015 generator learned to map the /debug:fastlink linker flag to the .vcxproj file property.
The :module:FindGTK2 module now configures the GTK2::sigc++ imported target to enable c++11 on its dependents when using sigc++ 2.5.1 or higher.
The precompiled Windows binary provided on cmake.org is now a .msi package instead of an installer executable. One may need to manually uninstall CMake versions lower than 3.5 before installing the new package.