The regular league season now kicks off in the last week of July at the earliest and should normally close within the last week of May, or the first couple of days in June at the latest before the relegation playoffs are drawn.
Also included is a revamp of the League Cup, which now has an extra round added to the competition to accommodate the extra 4 teams
Round 1: 48 teams - Leagues 1 and 2
Round 2: 48 teams - 24 winners from Round 1 + 24 Championship teams
Round 3: 32 teams - 24 winners from Round 2 + 8 lowest-placed Premier League teams
Round 4: 32 teams - 16 winners from Round 3 + 16 highest-placed Premier League teams
Round 5: 16 teams
Finally, the transfer window has also seen a revamp which now allows teams from 34 nations across Europe to operate for 360 days out of the calendar year, with the window opening on June 1st and closing on May 26th. With the exception of the "Transfer-360 - England" file (as the Premier League has its own nation rules for England), the other 33 Transfer-360 files can all be used alongside each other. If you'd prefer to just have the new transfer window without the new Premier League then the file is there to use instead.
This has been tested up to June 2030 and ran without any issues.
Extract the editor files to:
Documents/Sports Interactive/Football Manager 2020/editor data