Overview of the various update options for Joomla 5
Visforms and Subscription from version 4.4.1 upwards (4.4.x)
You can run Visforms and Visforms Subscription from version 4.4.1 upwards under Joomla 5.
In this case, make sure that the Joomla plugin Behavior - Backwards Compatibility is activated.
More about this in: Start on Joomla 4 with Visforms 4.
Visforms and Subscription from version 5.0.0 upwards (5.x)
You can run Visforms and Visforms Subscription natively under Joomla 5 starting with version 5.0.0.
Operating natively here means that Visforms is fully compatible with all new changes to the internal architecture and structure of Joomla 5.
In this case you can deactivate the Joomla plugin Behavior - Backward Compatibility.
More about this in: Update under Joomla 5 from Visforms 4 to Visforms 5.
Adjustments to your own Visforms Custom Plugins from version 5.0.0 upwards
If you run Visforms and Visforms Subscription from version 5.0.0 natively under Joomla 5, adjustments to your own Visforms Custom Plugins are necessary.
Instructions for updating your own plugins can be found here: Update your own plugins.
Instructions for correcting the code of your own plugins can be found here: Code correction of your own plugins.