SIM808 upgrade to 4G?

I use SIM808 with 4G and get no connection to network/carrier. My seller said SIM808 was capable for 2G,3G and 4G. Now I get mixed messages, and start to believe that only 2G is possible. If so, can I update firmware or something like that.

Hello; sadly, the SIM800 family only works with 2G. What might work with 2G is the simcard you put on it, but depends on the cellular network. Lots of people have been able to use any of the SIM800 products with 3G or 4G simcards, but only because those chips are used in networks that still have 2G capabilities.