Hey there
Were you thinking of doing a rollback of any update (plugin, theme, core) or just WordPress itself?
Also, why would you want to do that? Some more insights would be very helpful.
There is a great plugin that allows Plugin and Theme Rollbacks already:
https://wordpress.org/plugins/wp-rollback
{end shameless plug}
Note that we want users to always be on the latest and greatest versions of their plugins and WordPress itself. We’re looking into automatic rollbacks in case of fatal errors, but manual rollbacks are really too dangerous. That’s why I’d recommend using the plugin Matt suggested for now. Read the disclaimer though!