The T-Mobile version doesn't likely have the software in the carrier information to allow the visual voicemail.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
You’re buying directly from Apple. Which means no more financing your iPhone through your carrier or committing to a multiyear service contract. Your new iPhone will work with your carrier, so you won’t have to make any changes to your rate plan. And if you ever decide to switch carriers after you activate your iPhone with AT&T, Sprint, T-Mobile, or Verizon, you can easily do that, too.
Apple does not allow carriers to update ios software. All signs here is that Verizon will not add IEMI's for non-Verizon bought iphones to all of there data bases.
That is incorrect. The last 5 iPhones I have purchased, 2 iPhone 6 & 1 iPhone 6s & 2 iPhone 7, purchased unlocked directly from Apple, visual voicemail works just fine.
And I did not have to contact Verizon for it to work, either.
It is correct when you are with another carrier at the time you upgrade via the Apple upgrade program while you are with another carrier. Please read my original post. I had trouble initially moving to Verizon due to the same problem. A Verizon Corporate store employee was able to overcome my non-Verizon IEMI to activate my Max. I have numerous conversations with Apple Technical Support and Verizon Technical Support.
I suspect you already were a Verizon subscriber when you upgraded your iphones.