Convert old patch map (for example 1.26a) into SD only map

[TheExistance]

Of course the talk is about protected map, else it'd just be open map in Reforged Editor - Set SD Only - ??? - PROFIT

So, we know Reforged and its bad in maps with a lot of units, poor people with HD Graphics will start soon or later play with 10(1) fps and they will rage quit, so they question is - how to make map SD only, if its protected and edited in old patch? Change w3i file? I'd like to hear an answer