Joomla 4 is out there since August 2021. It brings some new coding styles with a compatibility layer for the old Joomla 3 way of coding. Event Gallery 4 supports Joomla 3 and Joomla 4, which blows up the code and complexity. There are only several months left where Joomla 3 is officially supported. I'm currently re-coding to support the J4 coding style fully.
With Event Gallery 5, I'll drop any Joomla 3 support. Event Gallery 4 will continue supporting Joomla 3, but will get only bug-fixes in emergency cases.
Do you need to worry? Not really, since all of you already made the jump to Joomla 4, right? ;) For those who have not, it is not that hard. Here is how I did it with several sites:
- Update to Joomla 3.10
- grab a copy of your Joomla 3 site with https://www.akeeba.com/products/akeeba-backup.html
- create a running server
- practice the Joomla 4 update and write down all the necessary steps. If you fail, return to step 3
- apply your steps to your production server
I had only a few issues. The template needs an update, that is for sure. Maybe you need to uninstall unused components and install all available updates for the rest.
There is an article for the migration: https://docs.joomla.org/Joomla_3.x_to_4.x_Step_by_Step_Migration