Apple has published a detailed article warning users about unauthorized modification of iOS. The article contains adverse issues experienced by customers who decided to “jailbreak”. Apple stated that iOS is designed to be reliable and secure from the moment that you turn your device on. As iOS contains security features which protect against viruses and malware.
Issues arising from “Jailbreaking”:
Apple states that the following can happen if you “jailbreak” your iPhone, iPad or iPod touch; security vulnerabilities, instability, shortened battery life, unreliable voice and data, disruption of services and inability to apply future software updates.
Instability means that frequent and unexpected crashes of the device will occur, alongside, freezes and loss of data. Disruption of service is where services such as iCloud, iMessage, Apple Pay and FaceTime may be disrupted meaning that they will no longer work as expected.
Apple strongly cautions against installing any software that hacks iOS. It is also important to note that unauthorized modification of iOS is a violation of the iOS end-user software license agreement and because of this, Apple may deny service for an iPhone, iPad, or iPod touch that has installed any unauthorized software.
You can read the full Apple Support article regarding unauthorized modification of iOS here.