Future-Proof Your API Integrations Before the 2026 Deprecation
Transition from legacy model names to V4 identifiers immediately.
Replace the legacy `deepseek-chat` and `deepseek-reasoner` model names in your code with `deepseek-v4-pro` or `deepseek-v4-flash` to avoid breaking changes.
The Scenario
You are maintaining an application or script that relies on the DeepSeek API and you want to ensure long-term stability and compatibility.
Before & after
Waiting until the July 2026 deadline could result in sudden application failure, requiring an emergency 30–60 minute fix under pressure.
Updating your integration to `deepseek-v4-pro` or `deepseek-v4-flash` now takes about 2 minutes and prevents service outages when the legacy names are retired.
The Prompt
Review this Python API implementation and update the model parameters from legacy names to 'deepseek-v4-pro' or 'deepseek-v4-flash' as appropriate: [PASTE_YOUR_CODE_HERE]
The legacy names `deepseek-chat` and `deepseek-reasoner` are scheduled for discontinuation on July 24, 2026. Transitioning early ensures you are using the specific V4 architecture intended for your task.
Source
Change Log | DeepSeek API Docs"The two legacy API model names, `deepseek-chat` and `deepseek-reasoner`, will be discontinued in three months (2026-07-24)."