12.3.1 update is draining my battery

I have a passion and hobby to go through complete literature and review of all iOS releases and needless to say I haven't missed iOS 12.1.3, 12.1.4 12.2, 12.3 & 12.3.1 assessment published on various news media and on Apple web page including leading news magazines (Forbes & Fortune Magazines).

The major takeaways from this iOS 12.3 update is Apple TV, Kids TV, The app is available on Samsung TVs, tvOS has been updated, AirPlay 2, Apple TV app,

And iOS 12.3.1 includes bug fixes for your iPhone and iPad. This update:

• Fixes an issue that could prevent making or receiving VoLTE calls
• Fixes issues in Messages that could cause messages from unknown senders to appear in your conversation list even though Filter Unknown Senders is enabled
• Fixes an issue that could prevent the Report Junk link from appearing in Messages threads from unknown senders
• 
  

No where I could find any link on the problem of "Battery Drain" faced by you. Introspect and have a complete and thorough check on the way you handle settings on your iPhone.

Read often for a peaceful life.

Solution. Protect & Prolong life of your iPhone's Battery:

1. 1. Put on Low Power Mode
   2. Put Auto Lock On (1 min):- with low power mode it will be 30 Sec
   3. Put Auto Answer Off
   4. Disable Push notifications for apps you do not use often
   5. Enable Auto Brightness:- Settings > General > Accessibility > Display Accommodations > Auto-Brightness [Enable]
   6. Manually lower brightness from Control Center
   7. If you Want to watch continuous Video. Stream it on TV or a Monitor
   8. Don't force close apps; Apps which are not on frontend screen are paused by the system to save energy. Apps require more energy to re-launch. Apps which are open in the background use large memory is a myth and quitting them is counterproductive
   9. Location services to be allowed only while using the app
   10. Set your iPhone to fetch email and calendar data from internet less frequently
   11. Turning off Background App Refresh 
   12. Charge before it drops below 20-30%
   13. Try connecting to trusted Wifi where ever available in stead of Cellular
   14. Enable Airplane mode in areas with bad cellular and wifi coverage. Your phone keeps trying for reconnection with the missing / weak network. This uses lot of energy
   15. Switch off Wifi & Bluetooth while in Roaming or Not in Range
   16. Enable "Wifi Assist" : Settings > Cellular or Settings > Mobile Data > Wi-Fi Assist [Enable]
   17. Periodically Check your Battery Health (Settings > Battery > Battery Health)

iPhone Battery and Performance

https://support.apple.com/en-in/HT208387

No, there are many, many reasons this can happen. Before judging the battery use I usually let the phone index, settle for 24 to 72 hours. If I'm still having excessive battery drain after that I go to Settings > Battery and see which apps are using the majority of my battery. In my experience Facebook and Instagram are 2 prime offenders and after an upgrade of each app the drain stops.

Hi All,

I'm facing the same issue with battery drain after updating my iphone 7 to IOS 13.2.1. I hope, they will fix it very fast as this is very annoying and should be checked before releasing to customers.. especially when it comes to battery performance.

Just because it doesn’t show up doesn’t mean it isn’t happening immediately after the update to most of us. I get what you’re saying but there is zero reason for this to be happening