Tittle is pretty self-explanatory. Trying to tame a harpy causes the game crash and say this.

The game crashed whilst ticking entity
Error: java.lang.NoSuchMethodError: 'int com.github.mechalopa.hmag.world.entity.HarpyEntity.getVariant()'

I tried taming it with golden apples. It only crashes when the strength level goes to 5 or above (Going from strength 4 -> 5 or 5 -> 6)
crash-2024-02-23_16.44.54-server.txt

This is possibly caused by HMaG API update. I'll check it.

Fixed in 0.x.22.