The positive experience of RFC 7807, whose journey began in 2016, is concluded (deprecation) but also confirmed with a new official proposition: the RFC 9457. The changes made are small but it is a suitable opportunity to analyze the evolution of this topic. Context The RFC 7807, and now the RFC 9457 which perfects it, was born after a period in which the Internet Companies have made it clear that the integration of the business, the eventual transformation of the company services into a plat