Notifications from Nest for our cameras have been working (click on the preview and it shows you a few second thumbnail) while our devices were using IOS 14 XX. Upgraded to 15.2 yesterday December 14th and now they do not work. Was just going to post this to another thread but the mod closed it while there were still people not having it resolved! This is an IOS issue with the Nest app. Is there an update now or coming soon?
