iPhone 15 Pro battery drains rapidly after iOS 26.1 update

Dear Apple Support Team,

I am experiencing significant battery drain on my iPhone 15 Pro since updating to iOS 26.1 last week. Prior to the update, my battery performance was stable, but now the phone loses power rapidly even when idle overnight.

Here are the details of my issue:

• Battery health is at 99%, so the hardware appears fine.
• I have disabled background app refresh for all apps except Google Maps and Find My.
• Location services are turned off for all apps.
• “Raise to Wake” is disabled, and Do Not Disturb is enabled during the night.
• I limit charging to a maximum of 85% and avoid dropping below 20%.
• Despite these precautions, last night the battery dropped by 17% while unused, leaving me at 20% in the morning.
• During normal use, the battery also drains much faster than before the update.

Could you please advise whether this is a known issue with iOS 26.1 and suggest any steps I can take to resolve it? If necessary, I am open to reinstalling the software or performing additional diagnostics.

Thank you for your assistance.