OpenAI is expected to be nearing an announcement around GPT-5.5, its next model upgrade to ChatGPT. A cryptic post on X includes a hidden teaser, suggesting the news is coming soon.

The message from OpenAI on X simply reads “NS41” with no additional context. Fortunately, some of the replies explain the hidden meaning found in those four characters.

“The text NS41 in the tweet is a Base64-encoded string,” says . “When decoded, it reveals: 5.5”

Another translates each character.

N = 14, S = 19 19 – 14 = 5 4 + 1 = 5 so NS41 = 5.5

So there we have it: OpenAI is readying the launch of GPT-5.5, it seems.

The announcement will follow a busy few days for the company. Last week, Codex for Mac was overhauled with computer use and more features that go beyond agentic coding.

This week, OpenAI released the vastly better ChatGPT Images 2 for higher quality image generation.