Are you having issue with any of your WordPress plugin?, Maybe after updating it to the new update you realise the version break your site.
Its not really advisable for you to keep plugin out dated, and you can also have reason why it need to at that moment.
To change your currently plugin version
- Make sure your WordPress is in the current latest version.
- Download this plugin Wp Rollback
- Activate it and, Click on Menu > Plugin > installed plugin > roll back > select the version you want it to turn to > save the setting.