which versions are you using? if its like 1.19 and 1.20, then you can just use 1. theres nothing stopping you from using it and the actual format of the pack is the same. something older like 1.8 will have different names which requires you to make 2 packs, thankfully there is a convertor online somewhere that does most of the work for you. and if going even further back to something like beta, the entire system is different, individual items dont have names, but theres a whole sheet of block and item textures. not sure if theres a convertor for that

The "red" thing that happens is just to tell you that the datapack/recoursepack may not work properly in this version. But you can still use it. Just make sure nothing major has changed between the compatible update and the one you are tryna load it in.