Retirement Date for GPT 4.1-nano-2025-04-14

Question

Retirement Date for GPT 4.1-nano-2025-04-14

Lu, Isabel (she/her/hers) 20

Hi,

Can you pls advise which is the official retirement date for GPT 4.1-nano-2025-04-14. In the Model Retirement page, it states as "2026-10-14". However, in the portal, it shows as "2027-04-13". Can you pls kindly advise which should be the correct retirement date? Thanks.

Regards,Isabel

SRILAKSHMI C 19,825 Reputation points Microsoft External Staff Moderator

2026-10-08T17:14:19.2833333+00:00

Hello @Lu, Isabel (she/her/hers)

Thank you for reaching out to Microsoft Q&A.

The retirement date depends on whether you are referring to the standard (base) model or a fine-tuned model.

For gpt-4.1-nano version 2025-04-14, the current Microsoft documentation shows:

Base model retirement: October 14, 2026

Fine-tuned model – training retirement: No earlier than April 14, 2027 (for existing customers)

Fine-tuned model – deployment retirement: October 14, 2027

Therefore, if you are using the standard/base gpt-4.1-nano model, October 14, 2026 is the applicable retirement date.

If you are using a fine-tuned deployment, the deployment remains supported until October 14, 2027. The April 2027 date applies to the training/fine-tuning phase, after which new fine-tuning is no longer available, while existing fine-tuned models can continue to be deployed until the deployment retirement date.

Regarding the April 13, 2027 date currently displayed in the portal, this does not exactly match the documented training retirement date of April 14, 2027. We recommend following the published Microsoft Learn retirement schedule for the applicable model lifecycle.

For reference, please see the Microsoft Foundry Model Retirement Schedule.

I Hope this helps. Do let me know if you have any further queries.

Thank you!

1 answer

Your answer

SRILAKSHMI C 19,825 Reputation points Microsoft External Staff Moderator

2026-10-08T17:14:19.2833333+00:00

Hello @Lu, Isabel (she/her/hers)

Thank you for reaching out to Microsoft Q&A.

The retirement date depends on whether you are referring to the standard (base) model or a fine-tuned model.

For gpt-4.1-nano version 2025-04-14, the current Microsoft documentation shows:

Base model retirement: October 14, 2026

Fine-tuned model – training retirement: No earlier than April 14, 2027 (for existing customers)

Fine-tuned model – deployment retirement: October 14, 2027

Therefore, if you are using the standard/base gpt-4.1-nano model, October 14, 2026 is the applicable retirement date.

If you are using a fine-tuned deployment, the deployment remains supported until October 14, 2027. The April 2027 date applies to the training/fine-tuning phase, after which new fine-tuning is no longer available, while existing fine-tuned models can continue to be deployed until the deployment retirement date.

Regarding the April 13, 2027 date currently displayed in the portal, this does not exactly match the documented training retirement date of April 14, 2027. We recommend following the published Microsoft Learn retirement schedule for the applicable model lifecycle.

For reference, please see the Microsoft Foundry Model Retirement Schedule.

I Hope this helps. Do let me know if you have any further queries.

Thank you!

Answer 1

Hey @Lu, Isabel (she/her/hers)

I checked my Microsoft Foundry portal, and it also shows April 14, 2027 (the difference could be timezones) for GPT-4.1-nano (2025-04-14).

Interestingly, that's also the retirement date listed for GPT-4.1 and GPT-4.1-mini in the official documentation, while GPT-4.1-nano is listed as October 14, 2026.

Technically, the date shown in Foundry should be the more accurate one. However, since the model is already marked as Legacy, I'd recommend planning a migration regardless.

If you need to continue using this specific model beyond October 14, I would suggest confirming the retirement date directly with Microsoft Support to avoid any surprises. You can fill a support request ticket here: https://portal.azure.com/#view/Microsoft_Azure_Support/HelpAndSupportBlade