I recently had to downgrade my Minecraft so I could continue playing on my own server that had not been updated yet. I searched around for a little bit and finally came across Minecraft Version Changer by Flippit, It’s an amazing tool and simple for anybody to use.
It requires Microsoft .Net Framework 4 which can be downloaded here
Once you have installed it you just load up the program and select which version you would like to downgrade or upgrade to and then just click “Change Minecraft to selected version”.
It’s so easy, anybody can use it.Minecraft Version Changer by Flippit Downgrade or Upgrade,