Something one of the producers - Matalas maybe? said they were working on a pitch but there was nothing official.
I prob saw it on Twitter, likely a recording or transcript from a convention.
Section 31 hasn't been given a release date, last I checked they had finished casting but hadn't started shooting.
So if SNW which is in the middle of filming now, has a release date in 2025, it makes sense that a movie that hasn't even started filming yet would likely be released in 2026, assuming they start filming within the next 6 months. Granted, a 2 hour movie might be a little bit simpler to shoot than a ten hour TV show, since it's meant to be a TV movie it probably have about the same budget as a full season.