Plugins and Add-ons: Plugins cannot be installed

Hello,

I'm new to Ilias and for some reason, I cannot work out how to install plugins correctly. It would be great if somebody could point out my hopefully obvious mistake.

• I have installed Ilias 5.4.4 using docker


• I have downloaded the plugin TestRepositoryObject by following the instructions given in the readme


• The plugin.php is in the path ilias/Customizing/global/plugins/Services/Repository/RepositoryObject/TestRepositoryObject/plugin.php

If I go to Administration->Plugins, the plugin is listed, but there is no option to update or install the plugin.

The same has happened with all other plugins I have tried to install. What am I doing wrong?

Thanks a lot,

Tobias