Since even minor releases can introduce new syntax that previously failed to parse, this happens more than just on major version numbers. For example: async/awa

Since even minor releases can introduce new syntax that previously failed to parse, this happens more than just on major version numbers. For example: async/await, formatting string literals, underscores in numeric literals, the list goes on and on. So you'll have to upgrade your formatter. And when you upgrade it, it may start formatting something differently than it previously did, even if that chunk had no new syntax.