The RFL have confirmed that the Championship and League 1 seasons will include promotion and relegation.
The Championship will adopt the same top six play-off system which was used in the Super League in 2020 to decide who will be promoted.
The games will be played over a three-week period from September 25 to October 10, and will be shown live on Sky Sports.
In League 1, which kicks off in May, the team finishing top of the table will earn automatic promotion. The teams finishing second to sixth will play in a five-team play-off series culminating in a Promotion Play-Off Final.
That will run for four weeks, starting the weekend before the Championship play-offs (September 18-19).
Clubs will be required to have played 70% of their league fixtures (16 out of 22 in the Championship) to qualify for the play-offs.
Meanwhile, the bottom two teams in the Championship will be relegated – irrespective of how many fixtures they have played.