Is there any one is facing an issue after the last iOS 8.3 update update

Try restoring to Factory Settings:

Restore To Factory: Connect your device to iTunes on your computer, backup, and then select Restore to Factory.

See here for more information on Restore to Factory: https://support.apple.com/en-us/HT201252

If this doesn’t work your device may have developed a hardware problem. Contact Apple Support: http://www.apple.com/contact/

The same thing happened to my phone two days ago. I backed up my phone twice prior to the update as I have never had a successful update without losing texts, photos, etc. After updating, my phone seemed normal and I used it for a few hours before getting the black screen with the Apple logo. The phone finally went from the apple logo to the plug into iTunes picture after several attempted resets of holding in power button with home button. When I plugged my phone into iTunes, it indicated that my phone was in recovery mode and said I had to restore factory settings. Knowing that I had backed up prior to update, this should be no problem. However, when trying to restore backup, I received the message that my backup file was corrupt and/or phone not compatible. I tried three times and got the same message. I also tried the steps other folks had given in the Apple forum, but nothing worked. My phone was wiped clean as I'd just bought it. After several hours of google searches, I found a program called decipher backup repair, https://deciphertools.com/ios/fix-corrupt-iphone-backup.html. I ran the free trial first and then shelled out the $30 to fix my corrupted files. This program was worth it to me. It fixed my corrupted iTunes backup and allowed me to retrieve every single file that was on my phone prior to the backup. I hope that this isn't the same problem you have, as I know the anger and frustration when you lose important files.

I am facing fast battery drainage after updating my iPhone 6 plus from 8.1.2 to 8.3.

Please help me out.