PDF Embed API - versioning

Just wondering how do I link to a specific version of the PDF Embed API from my web page. The concern is if I always link to the latest version - will this always guarantee backwards compatibility or is it possible that  things may start breaking.

By linking to a specific version it means we can upgrade to the latest version after successfully testing the latest version with our code. Is this possible with the PDF Embed API - or will you always guarantee backwards compatibility, so there is no need to link to a specific version of the PDF Embed API.