OpenAI Launches GPT-5.4 with 1M Token Context Window and New $100/Month Pro Plan

OpenAI has rolled out GPT-5.4 inside ChatGPT, describing it as its most capable and efficient model to date with support for up to 1 million tokens of context. Simultaneously, OpenAI introduced a new $100 per month ChatGPT Pro plan that bridges the gap between the $20 Plus and $200 Pro tiers, including unlimited access to GPT-5.4 and five times more Codex usage than the Plus plan. The company also released GPT-5.3 Instant mini as a fallback model for users exceeding rate limits and quietly upgraded the backup model that ChatGPT switches to when users hit usage caps. Additionally, OpenAI patched two serious security vulnerabilities including a DNS data exfiltration bug and a GitHub token exposure in Codex.