Every model OpenAI switched off this year got six months' notice. The security model got twenty days

On 11 September 2026 OpenAI added three lines to its deprecation page: gpt-5.4-cyber is deprecated, leaves the API on 1 October 2026, and developers should migrate to gpt-5.6-cyber. That is twenty days from the notice to the shutdown — and the number only means something next to the rest of the page, where every other deprecation OpenAI announced this year came with roughly half a year. The comparison sits on a single page and is easy to check. Sora 2 and the Videos API: announced 24 March 2026, shut down 24 September 2026. The transcription family, including whisper-1: announced 26 August 2026, shutdown 26 February 2027. Legacy audio and realtime models: 20 July 2026 to 20 January 2027. The GPT-5 and o3 snapshots, including the original gpt-5-2025-08-07: 11 June to 11 December 2026. The older GPT Image models: 2 June to 1 December 2026. The legacy GPT-3.5 and GPT-4 snapshots: 22 April to 23 October 2026. Six announcements, six windows between 182 and 184 days. Then one of twenty. OpenAI gives no reason for the shorter window, and the entry carries no note distinguishing it from the others — so the reason is not something we can report. Two things can be said from the page itself. First, unlike the Sora 2 entry, which lists no successor at all, this one names a direct replacement that is already in the API, so developers have somewhere to go; they simply have three weeks to get there. Second, gpt-5.4-cyber is a model sold for security work, and it is the only model on the page whose customers are being moved on a timescale measured in weeks. For anyone choosing a model to build on, the deprecation window is the practical measure of how long that decision holds. A six-month standard is long enough to plan a migration around; a twenty-day exception, announced without explanation, is a different kind of commitment — and it is worth knowing which one applies before the work starts.