Often when Omeka updates it requires updates to modules and themes you are using in your install. The following links contain the latest version of all public modules and themes:
If you had your install set to automatic updates you may find that the install is broken as a result of the update. An easy way to identify the reason for the issue is to turn on error reporting in Omeka which will show more detailed error messages. You can do this by editing the .htaccess file for your install following the guide at Retrieving Error Messages - Omeka S User Manual
In almost all cases we have found broken installs are the result of using themes or modules that have not been updated to the most recent version. The installer only handles the update process for the core Omeka S application and does not manage your modules and themes.
For users who decide to handle this major upgrade manually, you can roll the site back to a previous version using Installatron and then turn off automatic updates to remain at the current version on your Omeka S install until your site is compatible with the upgrade and you are ready to make the jump.
Please keep in mind that while Reclaim Hosting is happy to build installers for popular educational applications like Omeka, our resources are limited at troubleshooting third party software and the best avenue for support is the Omeka Forums. Thank you for your understanding.