Gemini 3.5 Pro Has Vanished, and Google Has Gone Quiet for Four Months

Four months after Sundar Pichai announced onstage at Google I/O that Gemini 3.5 Pro would roll out to all users the following month, the model still has no API version number, no price and no release date. Instead, Google has kept shipping new Flash variants, and according to SemiAnalysis, the flagship project has been quietly shelved.

The story begins at Google I/O in May. During a media briefing ahead of the conference, Google's chief executive assured reporters that the top-tier model in the 3.5 family wouldn't take long to arrive. 'We are also excited for 3.5 Pro... it will roll out to everyone next month,' he said at the time, according to accounts cited by Bloomberg and Mashable. June came and went, and Pro never appeared.

Three missed deadlines

Google pushed the launch back to mid-July, then to early August. Both of those deadlines also passed without an announcement. In July, the company limited itself to a statement that the model was being tested with partners: 'We're currently testing 3.5 Pro, an upgraded Flash model, and other models with partners,' a Google spokesperson said, as quoted by tech outlets tracking the story.

Meanwhile, competitors kept moving. Anthropic released Claude Fable 5 and a test version called Mythos during this period, OpenAI unveiled GPT-5.6 Sol, and China's Moonshot showed off Kimi K3 with 2.8 trillion parameters. Google's silence, coming from a company that just a year earlier had boasted about its lead in coding benchmarks, started to draw notice from analysts and investors.

Market reaction and internal frustration

A July 16 Bloomberg report on Pro's months-long delay coincided with a roughly 4 percent drop in Alphabet's stock. According to the same report, the model's performance on coding tests fell short of Google's internal targets, which Bloomberg wrote had caused frustration among engineers, researchers and managers working on the project.

caused frustration among Google engineers, AI researchers, and managers - Bloomberg

A shake-up atop Google DeepMind

On August 5, a leadership change took place that, in light of later reports, looks like a direct consequence of the slipping deadlines. Demis Hassabis, the public face of Google DeepMind and a Nobel laureate, moved into the role of chairman, while Koray Kavukcuoglu took over day-to-day management of the Gemini roadmap. The same day, Jeff Dean, one of the co-creators of the Transformer architecture that underpins most of today's large language models, left the company.

The fact that both departures happened on the same day, right in the middle of a crisis around the company's most important product, is hard to write off as coincidence. Outlets covering the AI industry have linked the reshuffle directly to the troubled development of 3.5 Pro and pressure to speed up work on its successor.

A quiet burial

In August, the analysis firm SemiAnalysis reported that Google had effectively canceled the Gemini 3.5 Pro project in its current form and shifted the team and compute resources to work on Gemini 4, which is expected to move to a monthly update cycle. Google has not publicly confirmed this, and the company still formally maintains that the model is 'being tested with partners,' repeating the same line it gave in July.

Instead of the promised Pro model, the market got a string of lower-tier variants: Gemini 3.5 Flash, 3.5 Flash-Lite, 3.6 Flash, and later 3.8 Flash along with a Cyber version for detecting security vulnerabilities. All were praised for token efficiency and speed, but none replaced the missing flagship, leaving the older Gemini 3.1 Pro as the top of the Gemini lineup.

What it means for Polish companies

For companies in Poland building products on the Gemini API, this has concrete implications: there's little point planning a migration to a model that formally doesn't exist and, unofficially, may never ship. Technical teams currently using Gemini 3.1 Pro should expect that Google's next top-tier model update could arrive directly under the name Gemini 4, with a completely different architecture, rather than as a delayed version of 3.5.

The episode also dents Google's image as the leader in the race toward AGI, an image Hassabis and his team have promoted at every other opportunity. The contrast between the public promises made in May and the actual outcome by September is, for market observers, one of the clearer signs that the pace of model development at the biggest players is starting to diverge from the pace of their press messaging.