Why won't my note 4 from Verizon switched to ATT not able to do system updates?

[Android Central Question]

My son has a note 4 that I carried over from Verizon to ATT. It has multiple system updates available. When I go thru the setting to check for updates, it shows they're available. When I click update, it comes up with an error and to check back later. I've checked back for many months & the same answer shows up. It will not update. My other son has a note 4 from ATT & it has updated several times. Why does the note 4 from Verizon not update but the ATT note 4 update. We have our cellular service thru ATT. I contacted ATT & about the Verizon Note 4 & they explain it doesn't have anything to do with them. That is it the phone itself. How do I correct this besides getting another phone for them? I'm not looking forward to a higher cell phone bill then what we're already paying. Any & all suggestions would be appreciated. TIA.

 

[Rukbat]

The one that doesn't update has the Verizon firmware in it, and AT&T doesn't send Verizon updates. Verizon doesn't update phones that aren't registered to them. Moving a phone off the network it's made for (say even moving from Verizon to using Verizon towers with Straight Talk) eliminates updates. That's just a fact of life.