I am running OS 10.15 Beta (19A536g) on a Mac mini. Clean install etc. I have seen from the Brammy thread (https://forums.macrumors.com/threads/catalina-apps-working-not-working.2183923/) that WhatsApp is supposedly working. Every installation of WhatsApp over the past months (now on version 0.3.4375) fails with the error message "... cannot be opened because its integrity cannot be verified" (see attached image). Am I doing something wrong? How did Brammy et al get it to work?