Short and lazy version:
New 2.2b4 available
http://users.alliedmods.net/~psychon.../sdkhooks/2.2/
New since last beta:
CS:GO support.
Fixed GroundEntChanged gamedata lookup.
Fixed one potential crash when bad or missing gamedata.
Improved error messages.
Known quirks:
For bots joining server, OnEntityCreated fires before SM thinks that the bot's client index is a valid entity. I haven't decided on the best way to fix this yet.
If no issues, I'll soon make this the official release as 2.1 is aging badly on some games.