- Replicated into the browser with Pouchdb version 3.1.0. This went well.
- Then with version 3.2.1 of Pouchdb. No problem.
- Finally went back to Pouchdb version 3.1.0. Got error of "VersionError".
I resolved the error by going back to version 3.2.1.
The hint came from https://github.com/pouchdb/pouchdb/issues/2603 which talked about "because indexedDB itself can only bump the version up but not down."
Hope this helps someone.