Only as a follow-up. My two 420s on 2.3.15 haven't had any issues in the past month. I turned the resolution down to 1080 about 6 weeks ago and formatted the card. Now it has filled the 256GB card...

Prior to 3.1.x app versions, the iOS app would reopen on the last used tab. For instance, with the app not running even in the background, I could open the app and it would start on the Cameras page...

@Riley_S When the camera reaches card capacity, it sporadically overwrites. I'll see a couple recordings from the current day but nothing on the day or two before. Go back 3 or more days and there's...

@Riley_S I've had a couple app updates, now on 3.1.2 build 1318. Things seem "better" but I've been reformatting when the cards get full and viewing response gets flakey. I have not seen any firmware...

Have the latest app update. Still have issues viewing recordings on my KC420WS when the 256 GB cards get "full". Reformatting makes them work again for a while.

@Riley_S If it helps, I can confirm that all of my cameras have 256GB cards and it does seem to occur more often when the card is nearing full capacity. I thought reformatting just got things going...