Mod compile using Java 8 fails with 'org/eclipse/core/runtime/IAdaptable has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0'

I was updating one of my mods.
https://github.com/zlainsama/PeacefulSurface/runs/3397747492?check_suite_focus=true

You need to update Loom to a newer version which bundles Java 8 versions of these Eclipse libraries (or use up-to-date java). The last java 8 version of Loom is 0.7-SNAPSHOT (the newer ones, 0.8 and 0.9, require java 16 like MC 1.17+).

This can also be worked around by ensuring fabric’s maven is first.