Nope. Fortunately they haven't made any such demand. That would be an odd thing for them to do.
It's possible they may invite people to voluntarily enter an agreement (let's call it a "license" relating to a new "game system"; "
GSL" for short) whereby they give them something new in exchange for ceasing distribution of such products.
But nope,
WotC aren't forcing anyone to do anything.
Regarding the d20 logo - that license was always revocable; it said so right in its own terms, which publishers (including myself) voluntarily agreed to. A six-month sell-off period is remarkably generous, given that the license only stipulates, I think, 30 days.