I have just phoned the manufacturer/distributor (new Coldtec) and received confirmation that connection to a timer is possible despite the electronic hygrostat. According to the technician, the dehumidifier switches on automatically as soon as the timer activates the power flow.
This means that the new model is identical in terms of compatibility with a timer to the "old" model which had a mechanical hygrostat.

I always have it set to "permanent" and control whether it runs via current there / current not there.