Can't downgrade from beta to stable

Created a Discourse server from DO. It was running v1.9.0 beta 10 +87.
When I try to use the stable version: 1.8.7, SSO stopped working and getting error like this.

Failed to create or lookup user: PG::RaiseException: ERROR: Discourse: email in users is readonly : INSERT INTO “users” (“email”, “name”, “username”, “ip_address”, “trust_level”, “username_lower”, …

I just switched back to the beta version and SSO is working for now
Anyone could help me where should I check?

You cannot go down versions, that is not supported.

Thanks for quick reply.
I updated by making “version: stable” in app.yml.
Is that mean I have to wait for stable build with higher version number?

No, you can rebuild or go to /admin/upgrade to upgrade, (but stable doesn’t get updated as often, obviously).

Wait, I think one of us is confused here.

@David_Park You created a new site, which was installed on tests_passed, version 1.9.0.beta10. Next you went into your app.yml file and switched to stable, rebuilt your site, which then caused you to be on version 1.8.7. @codinghorror please correct me if I’m going nuts, but that is going down in versions and we don’t support “backwards” database migrations.

That’s correct. The details of what’s happened is the current versions of Discourse have users.email marked as read-only in preparation for its eventual removal; the older version of Discourse expects to be writing that column.

Which reminds me … I need to drop the column now that we can use the rails 5.1 feature that marks the column unused without a monkey patch.

OK @tgxworld now dropped the email column properly per new pattern.