Released yesterday, both Mesa 18.1.8 as a bug-fix release and Mesa 18.2.0 as the latest full release of the open source graphics drivers are now out. As usual, the Mesa team are suggesting you wait for Mesa Mesa 18.2.1 if you plan to upgrade, at least if you want a fully stable experience.
For the RadeonSI (AMD) driver, it now has compatibility profile support up to OpenGL 4.4. This is quite important for historic reasons, since there will be applications and games that rely on it that won't be updated (including for us in Steam Play/Wine). Personally, I think that's one of the more important features of this release, since it will give users a better experience. RadeonSI also now has compute shader support in the Mesa shader cache.
There's also various improvements to the Intel ANV Vulkan driver, various performance improvements, bug fixes and much more. Since I don't personally use Mesa, having an NVIDIA 980ti I use their proprietary driver so I'm not exactly too up to speed on it all. Great to see it progress though! If you want a more in-depth look, Phoronix has their usual overview.