GPT-4.5 Deprecation from ChatGPT on June 27 — Transition to GPT-5 Series

OpenAI has officially announced the deprecation of the GPT-4.5 model in ChatGPT on June 27, 2026. After a 30-day migration period, the complete transition to GPT-5 series models will be finalized. Most users will not be affected, but those who manually select models or use the API should verify their setups in advance.

📑Table of Contents

1. Official Announcement and Schedule for GPT-4.5 Deprecation
2. Users Affected and Scope of Migration Impact
3. Step-by-Step Migration to GPT-5 Series Models
4. GPT-4.5 vs GPT-5 Series Spec Comparison Table
5. Frequently Asked Questions (FAQ)
6. Summary and Next Actions

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Official Announcement and Schedule for GPT-4.5 Deprecation

According to the official release notes, the June 2026 updates include the deprecation of GPT-5.2 and automatic migration to GPT-5.5. The model lifecycle follows a pattern where new flagship models are released regularly, and older models are deprecated after 30-90 days. GPT-4.5 follows the same schedule and is set for deprecation on June 27, 2026.

The migration window typically provides a 30-day grace period, with the switch to GPT-5 series completing by July 27, 2026. Source: OpenAI Help Center (June 2026)

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Users Affected and Scope of Migration Impact

Each plan (Free/Go, Plus, Pro, Business) has different usage limits and feature differences. Manual selection users and API users will feel the biggest impact, while most users will experience a seamless automatic migration. Review your plan details and update API keys or model parameters as needed.

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Step-by-Step Migration to GPT-5 Series Models

1. Select GPT-5 series from the ChatGPT model picker
2. Update the model parameter in your API calls
3. Perform verification tests during the 30-day window
4. Contact support if issues arise

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GPT-4.5 vs GPT-5 Series Spec Comparison Table

Item	GPT-4.5	GPT-5 Series
Release Period	2025	June 2026 onward
Context Length	128k	200k+
Inference Speed	Standard	Improved
Deprecation Date	2026/6/27	Ongoing

Source: OpenAI Official (June 2026)

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Frequently Asked Questions (FAQ)

What if I want to keep using GPT-4.5?

It will no longer be available after June 27, 2026. We recommend migrating to the GPT-5 series.

What should API users do?

Change the model name to a GPT-5 series model and run tests.

Will data be lost during automatic migration?

No. Conversation history and settings are preserved.

Impact on Business plans?

Admins received prior notifications. Check the dashboard for details.

How does performance change after migration?

GPT-5 series offers improved speed and accuracy.

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Summary and Next Actions

The deprecation of GPT-4.5 is part of OpenAI’s regular model update cycle. Complete the migration to GPT-5 series early and remember to update parameters for API users. Check the official release notes for the latest information.

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