"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Working with iPhone 4S Owners to Address Battery Life Issues
One user in particular noted a battery drain of 10% per hour even in standby mode. The user was able to replicate the issue with all features such as Siri and location services turned off, and even on a relatively clean phone with no apps installed, hinting that the battery drain was coming from a core functionality on the device. The user does report, however, that Apple has reached out in an attempt to research the issue, asking to install system monitoring software on the device to help figure out what is going wrong.
"I then got a call from a senior [Apple] engineer who said he had read my post and was 'reaching out' to users for data and admitted this was an issue (and that they aren't close to finding a fix!) and asked lots of questions about my usage and then asked if he could install the file below and that he would call back the day after to retrieve the info. I extracted the file from my Mac after a sync and emailed it to him. He was incredibly helpful and apologetic in the typical Apple way!"Apple has yet to offer an explanation for the battery life issue, but anecdotal reports suggest that corrupted contacts may be responsible. Some users have reported that a backup and restore through iTunes can help, but until Apple offers an official solution those affected by the issue may need to experiment with various solutions.