The file check warnings are because it is in beta. The forum is expecting a
CRC checksum on these files. Since the forum is in beta and these files are not in final form it would be useless to create a final checksum until a
RC version (release candidate) is created which i expect sometime in September.
In that case, you will most likely want to UNINSTALL the beta in its entirety and only use the RC version. Mostly to avoid a dirty database as tables and columns WILL change. Better to start from scratch then find out something is broken later on.
If you are using 2.1 in production DO NOT UPDATE to 2.2 Beta you will be sorry you did.
I also expect the UPDATE to 2.2 WILL break some of the Addons should you decide to upgrade it is advisable to WAIT until all your addons are 2.2 compatible OR uninstall/disable them for this process.
My $.02 i am in no way telling you what to do, just warning you before you decide to update what you may encounter during this process.