If you Flash ATH3 you would officially get OTA, but not with ATH4 even thought there both August patch which they basically are the same but AT&T decided to go with ATH3, Anyway the reason i asked about Visual Voicemail is cause if you had your older phone and had Visual Voicemail on it and still hasn't been deactivated from your older phone then your Note20 Ultra will fail in activating the Visual Voicemail, i had to deactivated it from my Note10 Plus, then my Note20 Ultra decided to activate my Visual Voicemail. Which i found it odd.
Sent from my Galaxy Note 20 Ultra using XDA Labs
I tried flashing ATH3 last night, but it would not work with my U1 phone (tried to flash from U1 and wanted an AT&T phone). The only thing that worked was the ATH4. so now I have the unlocked phone with the AT&T Wifi calling, Volte , etc but no software update button In settings. Now my question is when I do want to update, whether it is security or major updates (Android 11) and I want to flash with Odin, will I have to wipe my phone? If not, can I flash ATH3 and get the OTA without having to restore everything ?