Yomomma4life

My son has autism and is 8. I dont play this game but I find him mods that he wants. He watches youtube videos and points to it telling me he wants it. I try to find it but MOST are 1.8. I have forge installed and Optifine 1.12 and then soon 1.13. Hes SUPER into lucky block stuff. I have the lucky block mod installed and like 5 or 6 add ons, for the lucky block but he'll find some that needs loot++ and I can't get that to work and or he'll find older versions of lucky block add ons that don't work. I guess my questions are: is it possible to get an older mod to work with a different version of minecraft? is there some trick that I just dont know? I dont play this game but I have to do all the installing for my son so I guess that is why I am super confused. I've tried searching for answers but I guess I am not wording it right. I keep getting old content or stuff not pertaining to my situation. Like I'll dl the mod and drop the folder in add ons> lucky block but sometimes they do not show up with all the other stuff. Example: Frosty lucky block. He saw it on a video. I went and downloaded it. Dropped the folder in the add> lucky block He starts the game and the frosty block isnt in with all the other blocks.