Error When Updating To Joomla 4
Nicole Otto
I have been updating to Joomla 4 and I continue to get an error Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()
I have unistalled any of the plugins that have given me issues though I keep getting a notice that the SP Pagebuilder may have issues with the upgrade. I install the newest version and it still gives me an error when I try to do the upgrade. I have update and upgraded all of the components.
Paul Frankowski
Accepted AnswerHi Nicole.
Set that inside configuration.php file and you will see what element made a mess!
This is Joomla Basics Knowledge, webmasters should always enable Debug & Error Max (in Global Configuration) BEFORE updating to Joomla 4 or J5. Forgive me, but this is repeated like a Matra in every Joomla upgrade guide. In your case only file edition left. But don't worry, everything can be fixed.
Nicole Otto
Accepted AnswerI had our coder look at it and it was due to some Joomla 3 files that were being caught and not updating.