How do you update a mod you're coding to 1.15.2. I've never touched on this subject before.

I don't know if there is a more correct way to do it, but here's how I do it:

- Set up a 1.15.2 workspace with the mdk download and running the gradlew for your ide

- Copy the contents of the src folder from your 1.14 project to the src folder for the 1.15.2 project.

- Open the 1.15.2 project in the ide. There should be a bunch of errors.

- Go through each and every error and look for a similar way to accomplish the same task in 1.15.2.

 

The update from 1.14 to 1.15 is relatively simple compared to version changes where the entire code structure was rewritten (i.e. when number ids changed to namespaced ids, and  when data packs were implemented over hard-coded recipes and loot).

https://gist.github.com/williewillus/30d7e3f775fe93c503bddf054ef3f93e  has some info on 1.15 changes