While there are many good reasons to update to Apple's newest mobile software, a bug has made it to where you may want to double-check your iCloud settings after doing so.
Apple issued a warning to select users today, stating that a bug in the iOS 10.3 update caused some disabled iCloud features to be re-activated. A MacRumors user shared the email they received about the bug:
We discovered a bug in the recent iOS 10.3 software update that impacted a small number of iCloud users. This may have inadvertently reenabled some iCloud services that you had previously disabled on your device.
We suggest you go to iCloud settings on your iOS device to make sure that only the services you'd like to use are enabled.
Learn more about how to manage your iCloud settings or contact AppleCare with any questions.
The iCloud team
After the user checked his settings, he found Mail, which he usually has turned off for iCloud, was indeed activated.
According to MacRumors, it isn't clear how many users have been affected by this issue. We'd recommend checking both your iCloud settings and your email, to see if you've received a message from Apple.
Even with this inconvenience, we would still highly encourage updating your iPhone if you haven't already. iOS 10.3 was designed to correct some nasty hacks and bugs, so make sure you update to protect yourself.