Joomla 4 Upgrades from Joomla 3+
Be Careful Doing it Yourself
by Eric Peterson
While the latest Joomla 4 version is outstanding, being more light-weight and faster than previous versions, the upgrade from previous versions can be complicated.
If you're getting warning notices on your current website about the PHP version you are using, you can ignore it, but older PHP versions will no longer receive updates and your website could be vulnerable to hacks. If your PHP version is automatically updated, and you're currently using a Joomla 3 or earlier, you're website will suddenly stop working. Usually if this happens, you can just go onto your hosting platform and revert to an earlier PHP version manually to restore your website to functionality.
The newer Joomla 4 version is now working on PHP versions 8+.
Failing to remove any old incompatible components, modules, or plugins before the upgrade can cause your entire site to error. Many of these extensions that were installed on your old website are not compatible. So, you're going to have to go onto the extensions page of joomla.org to find new compatible programs. These include things like programs to build contact forms, calendars, galleries and more.
Also be aware of that your old template, which was good for every other version, is NOT going to work. So, you'll either have to buy a new template, or be prepared to modify the stock template yourself.
If you are going to attempt it yourself, follow the warnings and make sure you have a current back up of your website.
For this reason, I recommend reaching out to someone who really understands the Joomla platforms if you're wanting an upgrade.