okay - so what updraft up to know does & does not:
- the manual backup worked and it was also uploaded to dropbox
- the "daily" scheduled backup worked but was not uploaded to dropbox.
- a second try with the manual backup again worked but also was not uploaded to dropbox - last entry in the log file always says "dropbox access gained"
- furthermore, although i configured updraft to keep 1 update it did not delete the older updates from the "updraft" folder on my webserver.
- after deleting the older updates from the webserver folder manually they still appear in the list on the plugin's page to restore from
- at the top of the plugin's page where the scheduled times are listed it always says that no backup was finished successfully.
- after finding and deactivating the conflicting other plugin, scheduling now works with all options but still does not delete old backups nor upload backups to dropbox
- enabling the debug mode makes wordpress give this feedback: "Strict Standards: Only variables should be passed by reference in /homepages/2/d50914773/htdocs/sandbox-rmf/wpsb/wp-includes/pomo/mo.php on line 210" and due to this error message the scheduling options dropdown for files can't be opened