Will an at&t unlocked deviced be locked again with an upgrade.

[AC Question]

I m using an at&t unlocked device running adroid 5.0. What if i upgrade it with android 6.0 [obviously it has to be at&t customized android 6]? Will it become again locked or be unlocked even after the upgrade?

 

[Ry]

I m using an at&t unlocked device running adroid 5.0. What if i upgrade it with android 6.0 [obviously it has to be at&t customized android 6]? Will it become again locked or be unlocked even after the upgrade?

Are you referring to SIM unlocking or bootloader unlocking?