I need to configure my Activity App to send custom emails. My company needs to send a specfic message in German and with additional company specfic information every time a file is shared with a user.
Any hints on how I can modfiy the tempaltes used by the activity app ?
There you can remove the core folder, instead create the directory /apps/activity/templates and copy the files email.notification.php and html.notification.php from the activity app.
Make your customization, copy your theme to your apps directory and enable it. Make sure the theme directory is readable by your www user.
Also, there are some limits with the theme identifier, see this post: Activate a theme