OpenAI model names aren't that confusing, you just need to know we started with GPT-1, 2 and 3, then 3.5, then 3.5 Turbo, then GPT-4, then GPT-4 Turbo, then GPT-4o where the o means omni, except it didn't really end up being omni, then GPT-4o mini Then we switch to the o series, where the o now means OpenAI instead of omni, starting with o1-preview and o1-mini, then o1 drops the preview, then we skip o2 and they announce o3 and o3-mini, but o3-mini gets released first, meanwhile GPT-4.5 comes out and THEN GPT-4.1 because why not, alongside GPT-4.1 mini and nano, then o3 finally arrives with o4-mini even though there's no regular o4 Then we're back to GPT with GPT-5, mini and nano, followed by 5.1, 5.2 and 5.2-Codex, then 5.3-Codex, and yes there's also GPT-5.3 but ONLY Instant, no Thinking or Pro, then 5.4 brings the coding capabilities into the main model so we drop the Codex suffix, but hey mini and nano are back, then 5.5, then 5.6 where the names are now Sol, Terra and Luna Then GPT-6 arrives but only Astra at first, followed by Sol and Luna, no GPT-6 Terra this time, and exactly a week after GPT-6 Sol we get GPT-6.1 Sol with near-Astra performance at a much lower cost And that's just the quick version, wasn't that hard was it?