Why is my Android Os using 40% of My Battery after the 7.0 update

I have updated to 7.0 and seen really poor battery performance. The Android OS seems to be using 40-56% of the battery. I have contacted HTC who told me I will have to wait until the next update, has anyone had similar experiences/solutions?

Thanks

from Android Forums at AndroidCentral.com - Ask a Question //forums.androidcentral.com/showthread.php?t=773010&goto=newpost
via IFTTT