Callerlab are introducing changes to both the Mainstream and Plus programmes effective in September 2026.
The Current Programme has 67 moves (48 Basic + 29 Mainstream)
The New Programme (2026) will have a total of 50 movements and is , closely aligned with the Social Square Dance programme.

Here is a quick summary as I understand it as a dancer.
No doubt I shall be corrected if I am wrong.

Removed moves are the more complex ones (e.g., Spin Chain Thru etc) which have been shifted to the Plus programme.
There are No brand new moves, Nothing new to learn,  Just fewer moves to learn.
This should lead to Shorter classes, faster dancer gratification, easier recruitment. (Fingers Crossed)

What This Means for Clubs is that they can continue teaching the current lists until September 1, 2026.

After that, the new Mainstream list will become standard worldwide.
Plus dancers will see an expanded program, since dropped Mainstream moves are to be absorbed there.

In short, Mainstream 2026 = 50 Moves. Anything that is removed, moves to the Plus Programme.