Here are the names of previous membership levels that have been removed/discontinued.
Academy, Gold, Platinum, & Mastery.
Any members at the time these was discontinued will be able to retain their level of membership as well as the features that came with that level as long they remain at the level and their account is not canceled or disabled due to non payment. If one does cancel, upgrade or their account is disabled, they will no longer be able to rejoin or downgrade at the level again.