Many iPhone 6s, 6 plus and iPhone 7 users after upgrading to latest iOS 11.3.1 or 11.3 are facing issue with their iPhone home physical button. For many users the home button has stopped working after the upgrade and for some the home button is responding intermediately. Even after several hours of upgrade home button click is not working on iphone7 plus/6.
Even affected users tried to reset the phones many times but that does not seems to fix the issue. So while the Apple customer support centre report it as a bug in latest iOS 11.3.1 but for some users the customer care replaced the iPhones with new one. There are reports of completely original iPhones malfunctioning after the latest updates.
For some users the situation is even worst as iOS 11.3.1 upgrade just broke the speakers, vibration, and began crashing all the time. The sound seems to decreased after the upgrade and iPhone is not vibrating in iOS 11.3.1.
As the issue is not widespread across all iPhone devices so there are chances that some iPhone with hardware issue are facing the problem after the upgrade. So it better to get genuine bar appointment with Apple and get your iPhone checked as you may receive a new replacement.
One alternative for the issue is to rollback to older iOS version that you were using until Apple comes up with permanent fix for the issue. Hopefully we see the fix soon in iOS 11.4