I had some issues with synchronizing to a online storage. The sync allways stopped with error messages which should not appear if the deserve timestamp flag was set. But setting the preserve timestamp flag didn't work either.
In the GUI there is a rasiobutton to sync timestamps only. After one sync with this selection the error messages didn't occure again.
Secondly, after the change to daylight saving time my script uploaded all data again because of different time settings on online storage and my computer. A sync with "timestamps only" changed the timestamp without uploading all data again.
But again: I found the function in the GUI only. And I want to sync "timestamps only" via script