Minecraft 7.1.10 mods won't work in minecraft 8.1?

I keep downloading mods and mod loaders but they don't work. Please help and give an explanation.

Thank you in advance

Added (1). I meant to type 1.8 not 8.1

Guest

It's really simple. Mods for a previous verson don't work on later versions. You will have to find mods for 8.1.

Brett