The jump to 1.8 brought several "under the hood" improvements that changed the user experience:
Version 1.8 addresses the memory leaks found in earlier builds, making it much more accessible for players with mid-range hardware. Character Highlights Xtm Avengers Main 1.8
Install the core Xtm library before dragging the 1.8 assets into your "mods" folder. Why the Community Loves 1.8 The jump to 1