RC (Release Candidate) updates are intended for users who are interested in testing new features.

RC (Release Candidate) updates are intended for users who are interested in testing new features.

They may include experimental changes that are not suitable for those who prefer a stable experience or are not actively involved in testing
If you see an update and it has rc in the name of the update I would recommend not downloading and installing it.
Look before you try, RC is meant for testing not for those who don't want some risk.

In general you want the two pieces of TSS, the database engine MTAS or green IN icon running on the server and TSS to have versions that are sync'ed
Think RC is not for everybody, ok?  
Standard Public is for all clients or all users.