@Sav25 It turned out I was able to solve my problem, and it didn't require another change in the firmware. My steps: - Disconect all Decos from power; - Delete all Decos from the app; - Reset the ISP...

@Sav25 Having exactly the same problem. Mesh wi-fi around the house, 4 Deco M4 units. All working perfectly for a few years till I upgraded to this exact firmware. Direct wi-fi to the ISP router...