mobile

I am a Verizon Wireless customer who bought a T-Mobile Nexus 6 back when Verizon didn't sell it. It has been working great on Verizon's network. However, I haven't gotten the OTA for the 5.1 update yet and was wondering if it was related to the VW network vs TM phone. My phone is as I received it (meaning no unlocking or rooting). I've been an android user since the Thunderbolt but haven't dived into tinkering as I'm nervous to get my feet wet. Any suggestions on how to proceed or answers to why I don't get the OTA would be helpful. Thanks!