MojangsonParseException from 1.12.2 to new 1.13.2

There was such a problem that it produces an error in the self-written plugin: “java.lang.NoClassDefFoundError: net/minecraft/server/v1_13_R2/MojangsonParseException”
And indeed, there is no such class in 1.13, but in 1.12 it was. What should I do with these?

Update the plugin so that it doesn’t rely on inexistent classes?

The fact is that the developer making the plugin for the server left the project. I am trying to update the plugin so that it works