We have updated from version 4.0.1-b1 to 4.0.5, but the update script allways die:
Fatal error : Access level to Piwik\Plugins\ExampleTracker\Columns\ExampleActionDimension::configureSegments() must be public (as in class Piwik\Columns\Dimension) in /html/typo3/piwik/plugins/ExampleTracker/Columns/ExampleActionDimension.php on line 136
The Example* plugins were removed in Matomo 4 and one of the 4.0.* updates should have deleted them (as their Matomo 3 code wouldn’t work in Matomo 4).
It seems like it didn’t for you, so I’d recommend you to simply remove the ExampleTracker plugin.