1.6.4 or 1.7.2 Forge vanilla installs won't work. Nothing to do with mods. 1.7.2 won't even start, if nothing else, and that's still supported.
Regardless of how easy it can be to update mods the simple fact is that they don't or won't. These mods seem to get abandoned rather quickly. They seemed to work before Minecraft abandoned java.
I cannot start Forge 1.6.4 or 1.7.2. Clean install and downloads today from mincraft.net and minecraftforge.net (1.6.4, 1.7.2, 1.7.10). No mods, I click Play and it just CTD. Same thing happens on several PC's:
Nvidia GPU, Intel CPU
Intel CPU/GPU
AMD CPU/GPU
A couple mods my kids want to play haven't updated past 1.6.4 or 1.7.2 and won't work on 1.7.10.
Any suggestions?