GPT-5.5 is at the beginning of RLVR scaling, and future versions with the same pretrain will get considerably stronger in the coming months.
With GPT-5.x releases, OpenAI is taking advantage of RLVR scaling to blur the jumps in capability between different pretrains. GPT-5.1 ($1.25/$10 per 1M input/output tokens, knowledge cutoff 30 Sep 2024, context length 400K tokens) is followed by a slightly stronger GPT-5.2 ($1.75/$14, 31 Aug 2025, 400K), which is likely a better pretrain and a bigger model. Then GPT-5.3-Codex ($1.75/$14, 31 Aug 2025, 400K) is almost certainly the same pretrain, and GPT-5.4 ($2.5/$15, 31 Aug 2025, 1050K) is notably stronger than GPT-5.2, but still very likely the same pretrain (the change in pricing might be due to the change in context length). And now GPT-5.5 ($5/$30, 1 Dec 2025, 1050K) is a new bigger pretrain, stronger than GPT-5.4.
The strategy of "iterative deployment" seems to be about using RLVR scaling to release each pretrain with a little RLVR first, and then to scale RLVR for the same pretrain in subsequent releases in order to almost match the level of capabilities that will be achieved with a stronger pretrain that only uses a little RLVR, which is to be released after that. Thus GPT-5.1 is highly RLVRed, it's followed by GPT-5.2, which is a different pretrain that's RLVRed only as much as necessary to slightly overtake GPT-5.1 in capabilities. And then GPT-5.4 is again a highly RLVRed model on the same pretrain as GPT-5.2, which makes it almost as strong as GPT-5.5, the first release of a considerably stronger pretrain that's only RLVRed as much as necessary to overtake GPT-5.4.
This process allows OpenAI to keep releasing ever larger flagship models while mostly avoiding stark jumps in capability. For GPT-5.5 (which is the first RLVRed Opus-class OpenAI release), this suggests that it's at the beginning of RLVR scaling for its pretrain, and thus there is still considerable potential to its capabilities. GPT-5.6 will be using