Step 5.1 release date
ForecastStepFunlanguage model
Step 5.1 has not been announced. Based on how often StepFun ships new versions, our forecast is that it arrives around December 22, 2026, probably between November 22, 2026 and February 5, 2027.
The forecast
| Most likely | December 22, 2026 |
|---|---|
| Window | November 22, 2026 to February 5, 2027 |
| Chance it arrives in that window | About 18% |
| Follows | Step 5 (out October 8, 2026) |
| Based on | no earlier gap to learn from, so we assume about 75 days |
How we got this
StepFun is the maker of Step 5. We look at the gaps between its earlier versions (Step 5, 2026-10-08) and project the next one. It is a guess from a pattern, not news: the maker has not said Step 5.1 exists. This page turns into the launch page, with price and facts, as soon as the model shows up on OpenRouter, Hugging Face or GitHub.
Available now from StepFun
Step 5StepFun · language model
Oct 8, 2026released
Step 3.7 FlashStepFun · language model
May 28, 2026released
Step 3.5 FlashStepFun · language model
Jan 29, 2026released
Predicted automatically by Modelcast. Not affiliated with StepFun.