Step 1
Find aliases, snapshots, and fine-tuned references
Search for o4-mini, o4-mini-2025-04-16, and any fine-tuned o4-mini identifiers. Check defaults and environment configuration as well as application code.
October 23 shutdown
o4-mini shuts down October 23, 2026. Scan before the rename becomes an outage.
OpenAI lists o4-mini and o4-mini-2025-04-16 for shutdown on October 23, 2026 and recommends gpt-5.6-terra as the replacement.
What to check
Step 2
Move to the documented replacement intentionally
OpenAI’s deprecation table recommends gpt-5.6-terra. Do not assume the new model accepts every old request parameter unchanged.
Step 3
Validate tools, reasoning, and sampling
Migration guidance for newer reasoning models includes compatibility rules around tool calling, reasoning effort, and sampling controls. Replay representative production requests before the shutdown date.
The deadline is a shutdown, not a soft warning. OpenAI states that deprecated models are no longer accessible after their shutdown date.
Check the rest of the repository
Fixing the first error does not prove the rest of the codebase is clear. Sunset scans source text for scheduled OpenAI shutdown risk and shows severity before you pay.