Coolbooter is an on-device tool that can be used to dualboot any version from iOS 5.0 to 9.3.4 on armv7 devices. It can act as a practically untethered downgrade at the cost of some storage space, as long as your device is downgraded to iOS 8.4.1 or on any version with an untethered jailbreak. It's most useful when OTA downgrading isn't available for the version you want, or tether downgrading is difficult on your device.
Here's how you can add an image:
Here's how to make a list:
To learn more HTML/CSS, check out these tutorials!