We are talking about two different version here:
1. The NAACCR XML Specifications version
2. The NAACCR Layout version
The specifications version (currently 1.4) is tied to the syntax of the XML (when a tag or attribute is removed/added, or when the specifications change, like the maximum number of characters allowed for the NAACCR XML IDs).
The layout version (currently 180) is tied to the data items (that's the one the community is used to).
Both those versions can be updated independently of the other one.
In 2021, NAACCR will release a new layout (only describing XML since fixed-columns will be retired) and that layout will be version 210 (or v21). There will be a new base dictionary associated to that version.
At that point, either the specification version will still be at 1.4, or maybe it will have been upgraded to address minor changes to the specifications.
I hope this answers your question.