Gemini 3.5 Pro delays due to coding performance, upgraded Flash model in testing

In mid-May, Google announced Gemini 3.5 Flash at I/O 2026 and said the Pro version would arrive in June. On stage, Google said it was “showing great improvements.” That deadline has passed with no update on when to expect it.

In mid-May, Google announced Gemini 3.5 Flash at I/O 2026 and said the Pro version would arrive in June. On stage, Google said it was “showing great improvements.” That deadline has passed with no update on when to expect it.

According to Bloomberg, Google is “taking time to try to improve [Gemini 3.5 Pro’s] capabilities, particularly in coding.” In late June, “Google updated the data being used to train Gemini in an attempt to improve [coding] skills, but the results were disappointing.” That timeline suggests that development saw a reset between I/O and the missed launch.

It’s unclear how the latest models are performing in other domains. Gemini 3.1 Pro dates back to February. In a statement, the company said it is “currently testing 3.5 Pro, an upgraded Flash model, and other models with partners.”

Google also added: “We’re shipping quickly across a wide range of models while keeping them highly cost-effective for customers.” Since the developer conference, updates to the Gemini app have focused on improving the user experience and rolling out the Spark agent. Today’s article also has insight on the use of coding tools internally.

As of April, “75% of all new code at Google is now AI-generated and approved by engineers, up from 50% last fall.” Efforts to win at coding have also been up against some engineers at Google with a more purist stance, who believe that all important code should be human-written to adhere to Google standards, ex-employees said. Additionally, according to reports, engineers internally are facing AI capacity restraints with tools.

An effort to “unite the company’s internal artificial intelligence coding tools” is underway. In terms of developing AI coding tools for the public, Google DeepMind (AI Studio), Cloud (Vertex), and the Android team (Android Studio) all have their own efforts.