OpenAI is expected to make an announcement about the next model update for ChatGPT, known as GPT-5.5. A mysterious post on the X platform contains hints that this news will be coming soon.

NS41, the Key to OpenAI's Secret Message

The message from OpenAI on X simply states "NS41" and provides no additional context. Fortunately, some responses explain the hidden meaning of these four characters.

NS41

— OpenAI Developers (@OpenAIDevs) April 23, 2026

Razvan Girgiz says, "The NS41 text in the tweet is a Base64 encoded string. When decoded, it reveals 5.5."

Another X user named Nic translates each character.

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

It seems that OpenAI is preparing for the launch of GPT-5.5.

The announcement will come after a busy few days for the company. Last week, Codex for Mac was updated with more features beyond computer usage and agency coding.

This week, OpenAI launched significantly improved ChatGPT Images 2 for higher quality image generation.