iOS 9.3 Contains A Bug That Cause Stalls and Crashes on Some Phones

[Update: while Apple has not reported a fix yet (likely to appear as iOS version 9.3.1), it is believed that the issue is related to either 3D Touch and/or having certain thrid-party apps installed on your device.  The Booking.com app appears to be one, but it is still uncertain what causes the crashing, or what class of apps causes the issue.]

There is a strange bug that has been reported for iOS version 9.3 (and some older versions) that are affecting a variety of iPhone models where trying to open links in Safari and a number of other apps either doesn't work, or causes the app or phone to crash, freeze, or hang.  While primarily occuring on both the iPhone 6s and the 6s Plus, it has been occasionally been reported on some older phones and iPad models as well.  If you significantly use an iPhone or iPad for work and to browse the web, we recommend not upgrading to iOS version 9.3 until the problem has been resolved by Apple.

For more details, read this 9to5mac.com article about the bug.