Reported development
Gemini 3.8 Flash appears in internal testing
Google employees are said to have access to Gemini 3.8 Flash Preview on Jetski, shortly after the release of 3.7 Flash.

Google employees reportedly have access to Gemini 3.8 Flash Preview through Jetski. Early impressions describe it as noticeably better than Gemini 3.7 Flash.
Gemini 3.7 Flash arrived only around two weeks earlier, so this points to a quick follow-up. It is an internal-testing signal, not confirmation of a public release.
