@privsec Sorry for the late reaction.
I just changed some settings in app/data/apache/app.conf
<VirtualHost *:80> DocumentRoot /app/data/public/castopod/public
I also added these lines at the end of the app.conf:
php_value post_max_size 200M php_value upload_max_filesize 200M php_value memory_limit 128M
I think I found the hint in the cloudron docs for lamp and the castopod docs.
Happy to read that you found another solution.
Edit: specified the filename.