There are always some risks involved in upgrading to a newer OS version. You need to make sure that your site/app is compatible with any changes that had been made. I'd suggest taking a snapshot of your droplet and spinning up a new instance based on that snapshot to test the upgrade on first. Since you pay by the hour and you can destroy the test droplet when you're done, it will only cost you pennies. It might just save you a big headache.