v153.0 (2026-06-15)

⚠️ Breaking Changes ⚠️

Enrollment change events (visible to the UDL) now include the feature IDs of the features involved when possible. (#7391)
Removed NimbusInterface.getPreviousGeckoPrefsState since it is unimplemented and the underlying SDK method is only used by tests. (#7412)

update() no longer bumps times_used or time_last_used, this is done only via touch(). Verified that both Firefox Android and iOS already track password use via touch() and call update() only for explicit edits. (bug 2045032)

Fixed a bug where enrollment change events were not emitted for rollouts that re-enrolled after previously unenrolling. (#7391)
Attempting to opt-out from an experiment that is not currently enrolled is now a no-op. (#7399)
All enrollment updates (opt-in, opt-out, reseting telemetry identifiers, unenrolling for pref conflicts) now trigger feature invalidation in Android clients. (#7405)
Changing experiment and/or rollout participation no longer triggers a double update. Enrollment change telemetry is now appropriately triggered when this occurs. (#7401)

There are new separate DisqualifiedReason and NotEnrolledReason for global (experiment and rollout) opt-outs. (#7400)
The Kotlin client now has per-feature update notifications. (#7354)
The Nimbus client now understands Firefox Labs opt-ins and will not automatically enroll in them. (#7403)