your characters will be fine.. but the worlds will ONLY update with new content in areas you did not explore.. so if you have explored a lot of the current map you are on then there is a good chance you will find little to no areas that will have the things you need to progress in the game as new things are coming out.

This game likely has another 2-3 years before it is finished. They have 3 more major updates and we know those will take anywhere from 9-12 months most likely.