Migrate Legacy DeepSeek API Model Names to V4 Standards Early
Switch to deepseek-v4-pro or v4-flash to avoid July 2026 service interruptions.
Update your API model parameters from legacy names like 'deepseek-chat' to the new 'deepseek-v4-pro' or 'deepseek-v4-flash' identifiers before the July 2026 discontinuation.
The Scenario
You are maintaining a production application that uses DeepSeek for chat or reasoning and need to ensure service continuity before the July 2026 deadline.
Before & after
Developers would rely on generic model names like `deepseek-chat`, which will stop working in July 2026, potentially breaking applications. Manually troubleshooting a failed API connection can take 30–60 minutes.
Update your API calls to use the `deepseek-v4-pro` or `deepseek-v4-flash` model parameters to maintain uptime. This takes about 5 minutes to find and replace in your configuration files.
The Prompt
Review my current API implementation: [PASTE_CODE_SNIPPET]. Please update the model parameters to 'deepseek-v4-pro' for high-reasoning tasks and ensure the base_url is correctly configured for the V4 release.
The legacy names deepseek-chat and deepseek-reasoner are being phased out in favor of specific V4 designations. Note that deepseek-chat currently maps to the non-thinking mode of V4-Flash, while deepseek-reasoner maps to its thinking mode during the transition.
Source
Change Log | DeepSeek API Docs"To access the new models, the base_url remains unchanged, and the model parameter should be set to `deepseek-v4-pro` or `deepseek-v4-flash`."