Over there the protocol simply mandates both backwards and forwards compatibility. But often times the thing to is to reference another lexicon, or to create a sub schema.

So let's say in a lexicon called:

com.example.post

I have an author field, and for that field I want to reference the profile definition in another lexicon called com.example.user, I pop in:

"author": {"type": "ref", "ref": "com.example.user#/defs/profile"}

And that references:

"profile": {

"type": "object",

"properties": {

"handle": {"type": "string"},

"displayName": {"type": "string", "maxLength": 256},

"avatar": {"type": "string", "format": "uri", "nullable": true}

}

Then it's all just lego blocks and you can worry about them block by block.

But even if you have a breaking change and you come up with a new lexicon for it, all the other apps using the old lexicon will continue to use it, it can't be deleted, so you've not broken anything on their end.