Mod Con Boiler And Zones

Recent replies to a post on a new system design seemed to indicate that mod con boilers don't like or work well with heating zones. My house has a 1" pipe diameter series loop on the first floor, probably dating to 1950. The radiation fins are steel fitted over the pipe. My second floor is a separate zone with with regular baseboard from the late 1950's. There are two rooms with a baseboard in each room. I have a 26 year old Vaillant hot water boiler.

If I ever need to replace my boiler, will a mod con boiler work for me seeing that I have two zones? Being in Wisconsin, it appears that is my only choice after May of next year. Personally, I believe the payback on a high efficiency boiler would take too many years (at least in my case) to be economically feasible. Thanks.