With YourSites 1.9 you can run a pre-upgrade checker against each of your client sites.
- Compatibility of your PHP version and DB type
- Your PHP settings against Joomla 3.10/4.0 requirements and recommendations
- If you have the required and recommended PHP functions and extensions installed and enabled
- Your installed extensions to see if the extension publisher has a version that is compatible with Joomla 3.10 or 4.0 *
- If you already required extension version installed or that the required version CAN be installed in the version of Joomla currently running your client website *
- Extensions Reported as Compatible
- Extensions Probably Compatible
- Extensions Requiring Upgrades to be Compatible
- No Compatible Version Information From Update Server
- No Update Servers Specified
Usage Screenshots
After selecting sites to check select the menu item from the 'Core Software' or 'Joomla' menu item

Client sites check their compatibility status

Preview the basic extension compatibility in the status popup

Full information can be seen by clicking the Joomla icon in the site status icon block

Here you can see the Required PHP and DB Settings

and the recommended settings

and extension compatibility

* Extension & Template Compatibility
We use the information provided by the extension publisher about compatibity of extension versions with Joomla 3.10 or 4.0. You should use this as a guide to likely compatibility since we cannot guarantee that this information is correct or that the extension is actually compatible. You will need to confirm with the extension publisher that the extension version is compatible and ideally test the upgrade on a backup/clone website to make sure there are no unforseen problems and at the very least make sure you have quitable backups.