Several småförbättringar here and are included in this release. Actually, it contains the whole 352 improvements! Very improvements on language management in Joomla. And the editors TinyMCE 4.4.3 and Code Mirror 5.18.0 been with.
Memcache (a cache method to save directly in the server RAM) has received additional fixes and now works better.
Another good news for us as upgrading Joomla sites daily is that you can now go from Joomla 3.5 3.6.3 directly without having to land in version 3.6.0 first. Saves us a lot of time!
Read about all the improvements here: Joomla 3.6.3 Issues closed on GitHub