Backing up your iPhone or iPad to iCloud is a good idea, but when you upgrade phones, you might end up with multiple backups, including ones you don’t need anymore. OS X Daily shows you how to delete them.
By default, iCloud backs up all your iOS devices. If you set up a device as new, or your don’t restore from an iCloud backup, you can end up with multiple backups of the same data, which takes up a lot of space. Thankfully, they’re easy to remove.
Open Settings > Usage > Manage Storage
You’ll see all your backups, select one you no longer need
Tap Delete Backup to remove it from iCloud
Now, you should have a little more space on iCloud. Just make sure you keep around backups for any devices you still have and use.