MSSL Rules – Rev 08 07 2022 posted.
Primary change:
ARTICLE II PLAYER SUBSTITUTIONS
Substitutions for players rated 1 thru 5 will require the same or lower rating than substituted player. Substitutions for players rated 6 thru end of roster can be rated 1 level higher. For example, a player rated 5 can replace a player rated 6. Note: Players rated 10 thru 12 are no longer interchangeable.