deleting those files and injecting compatible ones might make your map work (but its long shot and you have to be pretty adept at wc3 modding/editor stuff). In my research (new jass and 1.31 object editor data not counting), wtg, w3i, and wct files are the things that prevent maps from being back-compatible (or forward compatible in some cases). Dev comment: By shifting the Orb of Fire into an anti-healing role, Human players will be better equipped to focus fire enemy units in the late game against powerful healers like the Death Knight. If the third party wc3 hosts abandon 1.26 in favour for shiny new 1.32+, then you could probably stop worrying about anything other than latest wc3 ver. New effect: Decreases the effectiveness of healing abilities and hit point regeneration by 35 for 3 seconds. A Silver lining is that Blizzard seems to try and fix back-comp issues but it will take several months just like it did with the 1.31 clown fiesta.
This is where protected maps bury themselves with all the irony the 2006-8 internet can muster, since they cannot be opened with world editor and re-saved to new format (nice job protecting your maps guys-from-the-past that-are-no-longer-around-to-provide-new-version!).
If your map is already not compatible with 1.26, and you don't want to hassle getting old ver or making map compatible with old ver, you'd have to recompile/resave it with new world editor. My prediction is that there would only be two standards, 1.26 (which is compatible with the third party nonsense), and whatever Blizzard shoves down our throats (just like they did with 1.31).
