Resolves NO if GPT-4.5 or GPT-5 (or similar) is released.
Resolves YES if a more capable successor is released with a different naming scheme. Does not resolve if "GPT-4 Turbo" is released (not a successor).
Doesn't resolve yes if they "boil the frog" and just update GPT-4 continuously forever.
A bit of ambiguity exists with the word "successor" in the sense that a sufficiently different agentic model might be released, but it has to be their most "general" model and beat GPT-4 in most respects other than cost or speed.
Since the creator is inactive, I've brought forward the close date just so that this market isn't forgotten about (traders - including me - will see it in their closed markets after it closes).
The date will be extended if OpenAI are yet to release a more capable model.