# Topic subscription on /iid/v1/{}/rel/topics stops working

Calls to /iid/v1/* on iid.googleapis.com stop working on September 29, 2027.

On September 29, 2027, endpoints matching /iid/v1/* will be decommissioned. After this date, calls to these Instance ID server APIs will fail. This change removes topic subscriptions and related features hosted on iid.googleapis.com.

## What to use instead

Use the FCM topic subscription API instead by sending requests to POST /v1/projects/{project}/registrations/{registration}/topicSubscriptions on fcm.googleapis.com, or use a Firebase Admin SDK release that calls it.

- API: iid.googleapis.com (iid.googleapis.com)
- Kind: Endpoint removal
- Announced: September 1, 2026
- Takes effect: September 29, 2027
- Calls after that day: fail
- Calls it hits: `/iid/v1/*`
- Source: [Announcement](https://firebase.google.com/docs/cloud-messaging/troubleshooting)
- Verified: October 29, 2026, against iid.googleapis.com's own pages
- Page: https://www.okapi.bot/providers/iid-googleapis-com/breaking-changes/topic-subscription-on-iid-v1-rel-topics-stops-working/

## iid.googleapis.com's words

> All the InstanceId server APIs and the device group feature are deprecated and will be decommissioned on September 29, 2027.

Okapi finds the calls this change hits in your repo and opens the pull request with the fix: https://github.com/apps/okapi-agent