Former or current owners of an iPhone 4S who live in two certain US states on the East Coast may be eligible to receive a US$15 settlement payment from Apple if they declare that their smartphone noticeably slowed down after the software update to iOS 9.
https://www.notebookcheck.net/Apple-agrees-to-pay-iPhone-4S-owners-15-for-sluggish-performance-after-iOS-9-update.617476.0.html