Apple released iOS 12.5.7 in January 2023 as a security update for devices that could not upgrade to iOS 13 or later. This update patched several critical exploits, including WebKit vulnerabilities. For users clinging to devices like the iPhone 5s or 6, this version is the final stop before obsolescence.
Here is the story of a persistent user’s journey to jailbreak an aging device running iOS 12.5.7 The Old Guard and the New Tools jailbreak ios 1257 windows
Alternatively, download the Chimera IPA from the Chimera official site and sideload it using Sideloadly by entering your Apple ID. Finalize on Device: How to Jailbreak iOS 12