No, there's no hardware upgrade path for the communications module. mBrace is also end of life and several services have already been terminated. The cars with LTE not only have an LTE communications module, but they also use a new online service platform called Mercedes me connect which replaces mBrace. There's no migration path for mBrace to Mercedes me connect. You have to trade in your car and get a newer one. There are Android based third-party head unit upgrades that essentially replace COMAND, so you get more modern functionality such as Android Auto and Apple CarPlay and various online services.
There are also systems like Hum by Verizon, which Mercedes actually partnered with that bring some of the online features back that mBrace had, via a Wi-Fi OBDII dongle and a phone app.
https://www.verizon.com/solutions-an...um-by-verizon/