DeepSeek Made Crystal Clear · chapter 3: Your First API Call
Legacy names mapped to current ones
2026-10-12
During the transition window, both old names quietly pointed at deepseek-v4-flash's two modes.
Below: the paragraph from the book that builds this idea, then the diagram itself (Figure 3.2), and a recap. About a minute of reading.
Two model IDs matter for new work as of this capture: deepseek-v4-flash and deepseek-v4-pro. You will also see two older names in tutorials and old code: deepseek-chat and deepseek-reasoner. DeepSeek's own changelog announced, on 2026-04-24, that both legacy names "will be discontinued in three months (2026-07-24)," and that during the transition window both legacy names silently point to deepseek-v4-flash, non-thinking mode for deepseek-chat and thinking mode for deepseek-reasoner. The announced window ran 2026-04-24 to 2026-07-24; whether the legacy names were actually turned off precisely on that date is confirmed only by secondary reporting rather than a primary DeepSeek changelog entry found in this research pass, so treat that exact completion date as secondary-sourced if you repeat it.
Recap
- The idea: During the transition window, both old names quietly pointed at deepseek-v4-flash's two modes.
- The picture: Figure 3.2, from chapter 3 ("Your First API Call") of DeepSeek Made Crystal Clear.
- Go deeper: the chapter builds this step by step, with recipes and sources at the end.
This diagram is one of many in DeepSeek Made Crystal Clear.
Every chapter opens with the gist, draws the hard ideas, and ends with recipes and sources.
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