IOS 10.3.1 battery drain issues on iPhone 7+

Since, updating my iPhone 7+, my iPad air 2, my iPad mini 3, my iPod 6 to 10.3.1, all 4 devices are having a major battery drain Issues. I have checked battery in system to see what is causing the issue, always seems the last app I run, is at 75% Home & lock screen around 50%. Everything else 1 to 3%.

Even if I do a full charge, reboot the device and with nothing running, they all are out of battery in the morning. Used to take almost 2 days for the phone to get that way, but now less than 6 hours it is out of charge, same with all the others. I have to leave them one of them on the charger over night just to have one of them with a full battery charge in the morning

before 10.3.1, my 3 month old iPhone would last almost 2 days...my iPad Air over night would be down to 80% but now 1% after 8 hours idle... same for the other 2. Looking at battery after they are idle overnight with a blank screen, home and lock screen is at 50%. Any idea's?