Fortunately I was now able to do the update to Version 6.2.2 through the internal update link of Acymailing. Simply great experiance! Only there was again this mysterious error message:
'JInstaller: :Install: File does not exist /var/www/.../apps/.../administrator/components/com_acym/extensions/mod_acym/mod_acym.xml
Module Install: Could not copy setup file.
Install path does not exist.'
Do you know what it could mean?'
Thanks and best regards.