XF 2.3 Forum down for over three months now, upgrade failed for some reason

[Parminder's]

I'm troubleshooting a XenForo installation where the upgrade to XF 2.3.8 was interrupted during the database schema migration (around February).

Current state​

• The xf_upgrade version is already recorded as 2030871, so running php cmd.php xf:upgrade reports that the installation is already up to date and does not execute any remaining schema migrations.
• However, the database schema is still in a pre-2.3 state. For example:
  
  • xf_widget is missing the position_overrides column required by XF 2.3.
• The interrupted upgrade also left duplicate/conflict tables, including:
  
  • xf_widget__conflict
  • xf_widget_1499079760
  • xf_session_install__conflict

Current behaviour​

• CLI commands work normally through cmd.php.
• Every web request returns an HTTP 200 with a blank page.
• The application appears to fail during rendering because the expected database schema does not match the actual schema.
• Attempts to rebuild data fail with:
  
  

  "You may not delete the default item."

Constraints​

• There is no usable backup to restore.
• Preserving the existing forum data is critical.

Question​

What is the safest supported way to force XenForo 2.3.8 to re-run its database schema migrations over the existing data?

Specifically:

• Can the recorded upgrade state/version be safely reset so the installer re-applies all pending migrations?
• Is there an official recovery procedure for an upgrade that completed the version stamp but failed partway through the schema changes?
• How can this be done without risking data loss or requiring a fresh installation?

 

[smallwheels]

If you have a running license extension it would possibly be worth opening a support ticked:

XenForo Help

Everything you need to get started and keep running

xenforo.com

 

[Rene_V]

Every web request returns an HTTP 200 with a blank page.

Are there any errors logged in recently in the server error log page?

The xf_upgrade version is already recorded as 2030871, so running php cmd.php xf:upgrade reports that the installation is already up to date and does not execute any remaining schema migrations.

What about trying it the old fashion way? i.e. through the browser?

 

[smallwheels]

Unfortunately I feel like it would have been best to restore to a backup immediately and retry the migration. Do you have any backup?

The origin post is not that long and it clearly states (in bold letters):

There is no usable backup to restore.