I agree with sigma delta. The published statement talks about guaranteed availability instead of End Of Life, but everyone I know assumes they'll announce EOL on Oct 1, 2023 (they almost always phase things out on Oct 1). It's usually a gradual thing, and at least spare parts generally continue to be available for at least several years (I think they typically promise 10?).
All that said, yes, you definitely should be starting to move towards 1500, unless there is a major technological hurdle preventing it.