Can Unlocked Verizon Iphone Work With Tmobile. Can I unlock a Verizon phone. Software updates may re-lock these devices as well.

Yes It will work but you wont have access to high speed LTE data Edge HSPA and HSPA only. They need to add iphone data plans to those simlines to get carrier data and provision them correctly on their system. If the phone has been activated on a Verizon Wireless account then it is unlocked to be used with another carrier.
This allows you to pay local rates rather than roaming charges or have a phone that doesnt work at all.
Everyones telling you its gonna work because it will. Now theres one additional bit of detail. The A2091 on the other hand is Apples GSM-only version and does not support CDMA networks. Things may be different for iPhone 6 but for every iPhone before including the 5 you cannot go from T-mobile or ATT or Sprint for that matter to Verizon.

