How will I be charged for changing a subscription during its validity?

As for the first activation, ZIP.ch will go through the usual payment process via the Datatrans transaction interface.

ZIP.ch may offer a reduction if you choose to upgrade for a higher price plan (with a similar duration to the current running subscription). The amount carried over will be calculated on the basis of the current contract (pro rata).

No refunds are expected for downgrades to a lower price plan. The contract will stay valid until its expiry date.