Depending on the add-ons: older plans have some stuff that's not compatible with new plans (Fav Numbers as an example), but if plans are compatible you can get all your add-ons. Give me the plans names for an exact answer
Indeed Daniel, the above user is correct. Moreover, based on your inquiry from yesterday, your add-ons could not be carried over for the plan you are seeking. Some plans are not, what we call "stackable".