The model card says: https://storage.googleapis.com/deepmind-media/Model-Cards/Ge...

> This model is not a modification or a fine-tune of a prior model.

I'm curious why they decided not to update the training data cutoff date too.

Maybe that date is a rule of thumb for when AI generated content became so widespread that it is likely to have contaminated future data. Given that people have spoofed authentic Reddit users with Markov chains, it probably doesn’t go back nearly far enough.