After updating to ios 11 on Sep 19, 2017 the battery is getting drained fast. It was not like that in previous version of 10.3.3. Any update why is it so.?
ios 11, Draining Battery Fast
As iOS 11 is now public, user-centric queries/comments such as this are perhaps best put to Apple's public community support forums, run by AppleCare, and/or Apple's twitter support account, vs. risking off-topic here in the DevForums, thanks and good luck.
Users can feedback via http://www.apple.com/feedback/ - Individuals using betas are free to use the Feedback Assistant; devs can use the 'Report Bugs' link, below right.