Constant API_VERSION 

pub const API_VERSION: &str = "1.1";

The protocol-compatibility version as "MAJOR.MINOR", distinct from the crate/stack version.

• MAJOR matches the /N in API_NAME and changes only on a breaking wire change (the transport already rejects a mismatched api, so an equality check on that is redundant).
• MINOR (API_MINOR) increments on EVERY surface change within a major — additive fields, new methods, or a strictness change like params validation — bumped in the same change that makes it. A client can guard with api_minor >= N for a feature it needs, or refuse a daemon older than a minor it requires. It never resets except on a MAJOR bump.