[PostFinance] What is the maximum time for which an authorisation is valid?

An authorisation’s validity period depends on the acquirer itself. By selecting “Operations”, “View Transactions”, and then clicking on “Show list” for a specific date and clicking on each PayID, you will see the days remaining before the authorisation for each transaction actually expires.
This number of days is given as an indication only. In the contract with your acquirer, you will find the exact authorisation period.