Battery losing charge after iOS11.4

I have the issue with IOS 11.4 draining my battery. I full charged my battery to 100% at night and in the morning I had 33% left!

No apps running, nothing new installed apart from the iOS update.

I know it is definitely the update as I have 2 IPhone 6s+ phones and the other one hasn’t been updated to the new IOS yet and battery remains charged fully give or take a few percent.

This needs sorted asap Apple as I can’t be running about worried my phone will shut down and its not as easy for me just to plug it in either, not the point!