J3.x:Developing an MVC Component/Upgrading to Joomla4/8/en

This step doesn't cover everything required to update a component from Joomla 3 to Joomla 4, just the aspects covered by the tutorial code. If you're upgrading your own Joomla 3 component then you may find it helpful to look at Potential backward compatibility issues in Joomla 4.