Delete a device from my developer account to increase the count
Is it possible to delete a device to increase the device count in my Apple developer account?
Answer
No. Deleting a device DOES NOT (immediately) increase your available device count. You have to wait until your apple developer account has been renewed, then visit the provisioning center and tap on devices.
You will see a message like this;
This is your ONE AND ONLY opportunity for the year to prune your device list. Click the devices you want to remove and tap on 'remove selected' at the bottom of the screen. Note that as soon as you (or another member of your team with sufficient rights) adds a device - INCLUDING AUTOMATICALLY PROVISIONED ones, you lose the ability to delete any more for the rest of the year (you can tell I'm speaking from experience here can't you?)
It's probably therefore better to remove lots in one go if you are getting close to the limit (and don't forget new devices launching each year etc) and then put back any that turn out to be needed.