Chrome 151 Ships and Finally Removes Manifest V2 Code

Chrome 151 reached stable this week, and buried in the release notes is a change that has been years in the making. Google has removed the last remaining Manifest V2 flags and code from Chrome's source tree entirely.

Manifest V2 was the extension platform Chrome used for over a decade, before Google introduced Manifest V3 with tighter restrictions on background scripts, network request handling, and remote code execution. The migration has been contentious, particularly with ad blocker developers, since V3's rules limit how content can be filtered compared with the old model. Google has been phasing out V2 support gradually since 2023, first disabling it by default, then removing enterprise policy overrides, and now deleting the code itself.

For most web users, this changes nothing visible. Chrome 151, build 151.0.7922.47 on Windows and Mac, behaves the same as previous recent versions for everyday browsing. The practical impact lands on extension developers and IT teams who may have been relying on enterprise policies to keep old Manifest V2 extensions running past their supposed end of life.

If your organisation still has internal tools or browser extensions built on Manifest V2, this release is the point where it still working because nobody flipped the switch officially stops being true. There is no fallback flag left to re-enable. Any extension still on the old manifest format will simply fail to load.

We think this matters beyond the extensions world too. It is a useful reminder of how long platform migrations actually take when a change affects developer tooling at scale. Google announced the V3 transition years before this final removal, gave multiple grace periods, and still needed this long to fully retire the old code path. Anyone planning a similarly disruptive platform change, whether that is an API version, a design system, or a build tool, should expect the everyone has migrated milestone to arrive later than the roadmap first suggested.

If you manage browser extensions for a team or client, now is the time to confirm nothing internal is still quietly running on Manifest V2, since Chrome 151 removes any possibility of it continuing to work.