Sorry if we didn't fix anything from RC2. After all the release was one day after, targetted at fixing immedate things.
Please repost any problems that were not corrected.
Known Issues:
"defined twice" language key errors. DON'T POST THEM.
amx_client_languages is not a registered CVAR.
If you have problems compiling plugins with amxxsc, use the old sc.exe from amxmodx-0.16. Remember, amxmodx 0.20 can load .amx files too. Posting compiler crashes is rather unhelpful. We didn't write the compiler and we know it sucks, we'll try to fix it the best we can.