Interesting, I read GGP as:

If they stopped learning (=including) at march 31 and something popup on the internet on march 30 (lib update, new Nobel, whatever) there’s many chances it got scrapped because they probably don’t scrap everything in one day (do they ?).

That isn’t mutually exclusive with your answer I guess.

edit: thanks adolph to point out the typo.

Maybe I'm old school but isn't the date the last date for inclusion in the training corpus and not the date "they stopped training"?