Released just over two years ago, the checkra1n jailbreak has proven to be particularly resilient because of the hardware-based checkm8 bootrom exploit that powers it. The checkm8 exploit targets A7-A11 devices (up to and including the iPhone X), and due to being hardware-based, Apple can’t patch it for those devices already in circulation.
Here’s how you can jailbreak A7-A11 devices running iOS 14.6-14.8.1 with checkra1n