Question [Q] OTA past ME7

So I really wanted to get an AOSP ROM after using a GNex for the last two years and after a few months with an S4 with ME7 I realized it would never happen. So I'm looking to sell the S4 with ME7 and have already replaced it with a Moto X Dev Edition.

That being said I broke the 4G LTE SIM compatible with the S4 before I threw it away and now after using ODIN to get the S4 back to stock ME7 the Software Update won't allow me to update to MDK or beyond. I get a message saying "Service Unavailable" "Software Update is temporarily unavailable. Try again later."

I want to make sure anyone who buys the device via Swappa or eBay will be able to update it if they desire.

I feel like maybe it's an issue not authenticating through Verizon's network, so with all that, should I be able to update it if I had a valid 4G LTE SIM in it?