You can read the official announcement blog post at https://blogs.embarcadero.com/announcing-the-availability-of-rad-studio-12-1-athens/
For Delphi developers doing mobile, having Android API level 34 support avaialble now is really great. For each and every Delphi users, the new editor split views is just great!
More information at https://docwiki.embarcadero.com/RADStudio/Athens/en/12_Athens_-_Release_1 and the list of bug fixed at https://docwiki.embarcadero.com/RADStudio/Athens/en/New_features_and_customer_reported_issues_fixed_in_RAD_Studio_12.1