There are just under two dozen additional commits in X.Org Server 1.8.1 RC2, with notable changes being the RECORD extension is now enabled by default and the SHA1 implementation is picked in a slightly different order. There's also a variety of other fixes in RC2.
"Please test this, I don't think I'll merge much this week but really crucial issues. So expect this one to be quite close to 1.8.1," said Peter Hutterer in the xorg-server 188.8.131.522 announcement. Meanwhile all new development activities are going towards X Server 1.9, which should arrive in August.