Represents the "Version" entry of the catalog dictionary object.

It is an optional entry defined as part of the PDF 1.4 specification.

It contains a string representing a PDF name object.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 28, page 73.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 3.25, page 23.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 29, page 98.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 242, page 458.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 245, page 555.

The Version entry in the catalog, when present, overrides the header version of the PDF file. A writer may use this to update the effective PDF version during an incremental update without modifying the file header.

The effective version of a PDF file is the greater of the header version and the catalog Version entry. Readers must check both when determining the set of features they must support for the document.