Originally published in July, 2017, ISO 32000-2:2020 is a so-called "dated revision" of the first PDF specification developed within the ISO working-group structure.
In 2017 the initial edition of PDF 2.0 was the culmination of nine years of work by a dedicated group of approximately 30 subject-matter experts from around the world. The 2020 edition continues the refinement of the venerable PDF format, originally published and made freely available by Adobe Systems in 1993.
Although it is an open standard one major difference as compared with versions of PDF up to 1.7; since ISO holds the copyright PDF 2.0 is not freely downloadable. Any subject-matter expert who is a member of the PDF Association (an ISO Category A Liaison organization) or whose country is a member of ISO's TC 171 SC 2 can join other experts and help determine the nature and direction of the world’s de facto electronic document format.
This dated revision of PDF 2.0 includes a number of corrections and improvements and replaces the 2017 edition.
The PDF Association also maintains an archive of documents, many originally published by Adobe Systems, used as normative references (and thus necessary to complete implementation) in ISO 32000-2. Many of these documents are freely downloadable. A current list of PDF-related ISO work is maintained here.