iOS 10 means it's time for iPhone 4S owners to move on - CNET
iOS 10 Beta 4 Download Now Available For iPhone, iPad, iPod touch | Redmond Pie
iPhone 4s - Wikipedia
iOS 11 will render older iPhones, iPads and apps obsolete | iOS | The Guardian
Review: Apple iPhone 4S | WIRED
Download iOS 5.1.1 For iPhone 4S, 4, 3GS, iPad And iPod touch [Direct Links] | Redmond Pie
Apple Reminds iPhone 5 Owners to Update to iOS 10.3.4 by November 3 - MacRumors
[question] Recently got my hands on an iPhone 4 running iOS 7.1.2. Should I jailbreak it? Btw it's a 32gb white, I also need to replace the battery. : r/LegacyJailbreak
Apple rilascia iOS 9.3.6 e iOS 10.3.4 per i vecchi iPhone e iPad. Ecco cosa cambia e perché è da fare | Hardware Upgrade
How to get iOS 10 on iPhone 4/4s/5/5c/5s/6 and above - YouTube