Generations
Which format the shipped SDK writes, which one the specification defines, and how to use both documents without mixing them up.
Two documents describe a record format, and they describe two different generations of it. Knowing which one applies to you takes one sentence: if you installed the SDK, this site describes what your code writes.
Two sites, two jobs
This site documents the format the mintBlue SDK writes today, plus the product around it. sdxprotocol.org documents the protocol and a later generation of the same format.
The two are not wire-compatible. A record written by the shipped SDK is not a record as the current specification defines it, and reading one document while building against the other is the mistake this page exists to prevent.
What that means in practice
Each side describes its own mechanism. This site says how the shipped format stores a record, the specification says how the specified format stores one, and neither claims anything about the other's behaviour in either direction.
Three consequences follow.
Use the format pages here for integration. What your installed SDK emits is documented under Reference, one page per format. That is the document to check a byte against.
Use the specification for the model. The envelope model, key derivation, addressing and the audit trail are specified at sdxprotocol.org, and the concept pages here link it rather than paraphrasing it.
Do not read a version number as a schedule. Nothing here is deprecated, nothing is withdrawn, and no migration is announced. The format the SDK writes today is the format it writes today, and it is the one the platform runs on.
Reading the specification
The normative document is specification v0.1, version-pinned deliberately, because the protocol side versions its specification and an unpinned link would quietly change meaning under you.