Spigot 1.13.2 final
ExtraHardMode 3.14.alpha-f00ecfd

api-version: 1.14

is not supported in Spigot 1.13.2. Use

api-version: 1.13

if support for 1.13.2 is intended. If support for only 1.14.x is intended, then no change is needed, other than notation of that fact.

Yes, 1.14 support is intended here. I think I may have already started using the new Materials which 1.13 isn't aware of.

I guess I could look into trying to update plugins without using a newer API, but IMO it'll just make the eventual-needed updating a lot harder to do when a new feature or otherwise necessitates updating (that, and it's harder to see what API methods were or were not dropped, e.g. getTitle on Inventory).