GPT-5.2 and GPT-5.3-Codex have been sunset in Codex with ChatGPT subscriptions

Compute is limited. They will need to sunset some models to move onto new ones. It’s always been this way. If they were to stick with 5.3 and never release 5.6 they would fall behind the competition. But nevertheless feedback is clearly useful because it helps them know when they’ve done something right with a model.