I'm using TYPO3 9.5.5 and have installed pits_downloadcenter 3.0.1 extension.
I am encountering errors after installation in 'Extensions Manager'.
Call to a member function admin_get_tables() on null" in "typo3conf/ext/pits_downloadcenter/class.ext_update.php line 68"
Do you have the extension "TYPO3_DB compatibility layer for TYPO3 v9.x" installed? It seems that the extension pits_downloadcenter still relies on the deprecated database functionality.
You should report this issue in the issue tracker of the extension.