iOS 12 Jailbreak Status
You can jailbreak newer versions of iOS 12 using one of the latest jailbreak tools, but it's unclear if the tool works with iOS 12.5.1.
The developers behind the "unc0ver" jailbreaking tool for iOS have released a new version, 5.0.0, that's compatible with the latest version of iOS 13 and most versions of iOS going all the way down to iOS 11.0. Unfortunately, iOS 12.3-12.3.2 and iOS 12.4.2-12.4.5 aren't supported.
There's also another jailbreak tool (checkra1n) that works with iOS 12.3-iOS 13.5 so you'll want to look into that one as well.
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