Linux gamers and enthusiasts should really be running Mesa 17.0 if you don't want to risk running Mesa 17.1-devel Git, but for those still on Mesa 13, it's continuing to receive fixes. There are more than one hundred patches queued under their new stable nomination scheme for getting fixes backported to current Mesa stable series.
Some of the changes include GLX/EGL fixes, crash fixes affecting all Gallium3D drivers, RadeonSI tessellation shader fixes, improved compute shader support for Nouveau NVC0, many OpenGL/Vulkan Intel driver fixes, and over a dozen fixes for the Radeon RADV driver.
Details on the Mesa 13.0.6 release candidate can be found via Mesa-dev. Velikov is planning to officially release Mesa 13.0.6 before the weekend.