(*) n u d : new / updated / deleted since previous version.

(**) Usage: The indications Mandatory / Conditional / Optional are to be understood in respect of the actual level of the Data element:
  example given; some party data-set as a whole can be optional, while, if present, the party's name within that party data-set can be mandatory.

Remark: in UN/Edifact, "Mandatory / Conditional" are notions used within the standard. And within edi-guides (a refinement of a standard) the "Conditional" can become "Required / Optional / Dependent / Advised / Not used". Ideally we should implement the same ideas.

(***) Remark: In 2020 things evolved into another "approach A" and then yet another "approach B" - It is that "appoach B" which you see here - That "approach B" is the basis of the EDIMERX development.
In TB2-XML "Namespace 2018" (as well as in eEG7-UN/CEFACT), things were/are structurally different.
EDIMERX is supporting the transition from Edifact (messages) to JSON (API's).
The so-called "Business API's" are what comes next / after such transition-phase - and there things will be structurally differrent again.