This question already has an answer here:
When Minecraft updates (It recently updated to 1.8) Minecraft mods no longer work. I have tried setting the Minecraft game back to an earlier version but most of the mods do not work anymore.
Do the mods need to be updated to work with the newest system regardless of updates? Or can mods remain the same and the Minecraft client just need to allow mods to be readmitted into the file system?