I am updating CiviCRM from 4.7.27 to 4.7.31 on WordPress 4.9.4. Other than CiviCRM, everything is up to date.
I've thoroughly Googled the problem, and have tried three times to do the update. But the "Your database has already been upgraded to CiviCRM 4.7.27" problem persists. I've followed the relevant portions of Upgrading CiviCRM for WordPress for current versions of WordPress and CiviCRM.
In particular, in response to problems other people have had, I've:
- Completely deleted my /wp-content/plugins/civicrm folder via FTP (I didn't just rename it).
- Downloaded a fresh copy of CiviCRM 4.7.31, unzipped it locally, and uploaded the civicrm folder to /wp-content/plugins. I confirmed that the remote copy of civicrm.php references version 4.7.31 in the header.
- Deleted the files in /wp-content/uploads/civicrm/templates_c.
- Cleared the browser cache (I'm using Chrome).
- Searched the site files for a rogue civicrm plugin directory. There is none.
All of this in addition to all the other relevant steps in the Upgrading wiki article. (We're not using localization files.)
Nothing works, and I continue to be haunted by "Your database has already been upgraded to CiviCRM 4.7.27" when I run the upgrade script.
What could I be missing? What is causing the problem?