Users Report GPT-5.1 (Thinking) as Strong Successor to GPT-4o After Official Discontinuation

After OpenAI quietly phased out its widely praised GPT-4o model earlier this month, users across creative and technical communities have been scrambling to find a suitable replacement. Among the most surprising and positively received alternatives is GPT-5.1 (Thinking), a lesser-publicized variant that has quietly gained traction among writers, researchers, and content creators. According to a recent thread on Reddit’s r/OpenAI community, user ShiningMagnus reported that after dissatisfaction with GPT-5.2, switching to GPT-5.1 (Thinking) delivered results nearly indistinguishable from the now-discontinued GPT-4o.

The user, who primarily employs ChatGPT for creative writing, research, and idea journaling, noted that pairing GPT-5.1 (Thinking) with custom personalization settings—easily configured via simple text prompts—yielded highly satisfactory outcomes. "I don’t really see too much of a difference between 4o and 5.1 (Thinking)," the user wrote, adding that the model’s ability to retain context and generate nuanced responses made it feel like a natural evolution rather than a downgrade. This sentiment echoes across multiple user reports in the thread, where dozens have since confirmed similar experiences, particularly in long-form ideation and iterative drafting.

While GPT-5.2, OpenAI’s flagship release, was marketed as more powerful and efficient, early adopters have noted inconsistencies in tone, over-cautious filtering, and reduced creativity in open-ended tasks. In contrast, GPT-5.1 (Thinking) appears to retain the more conversational, exploratory style that made GPT-4o a favorite among creatives. The "Thinking" mode, which emphasizes step-by-step reasoning and internal reflection before output, seems to align well with users who value depth over speed.

Notably, the user acknowledged that they have not encountered censorship issues, though they conceded that others have raised concerns. "I’ve heard censorship complaints about this one, but... I don’t think what I use GPT causes me to run into censorship issues," they wrote. This suggests that the perceived restrictions may vary significantly based on usage patterns, region, or prompt framing—highlighting a broader debate about AI alignment and content moderation in commercial models.

OpenAI has not officially commented on the resurgence of GPT-5.1 (Thinking), nor has it confirmed whether this version was intentionally preserved as a legacy option. However, internal documentation and developer forums suggest that GPT-5.1 (Thinking) was originally developed as a research variant focused on cognitive modeling, and may have been repurposed for public access as a stopgap after GPT-4o’s removal. The model’s availability appears to be inconsistent across platforms, with some users reporting access only via API or custom chat interfaces, rather than the standard ChatGPT web interface.

For professional users reliant on AI for ideation, the return of GPT-5.1 (Thinking) may signal a growing disconnect between corporate product strategy and user needs. While OpenAI continues to prioritize scalability and safety in its flagship models, a significant segment of its user base values flexibility, creativity, and consistency over algorithmic caution. As demand for this version grows, analysts speculate that OpenAI may eventually formalize GPT-5.1 (Thinking) as a dedicated tier—perhaps under a "Creative Mode" or "Legacy Reasoning" option—to satisfy niche but vocal users.

For now, the message from the community is clear: when innovation outpaces user experience, sometimes the best solution is not a new model—but a return to an older one, refined by user feedback and quietly kept alive.