Editing PKZIP (section)

==.ZIP file format==
{{Main|ZIP (file format)}}

To help ensure the interoperability of the ZIP format, Phil Katz published the original .ZIP File Format Specification in the APPNOTE.TXT documentation file. PKWARE continued to maintain this document and periodically published updates.<ref name="Buchholz, JMU, 2015"/> Originally only bundled with registered versions of PKZIP, it was later available on the PKWARE site.<ref name="Buchholz, JMU, 2015"/>

The specification has its own version number, which does not necessarily correspond to the PKZIP version numbers, especially with PKZIP 6 or later. At various times, PKWARE adds preliminary features that allows PKZIP products to extract archives using advanced features, but PKZIP products that create such archives won't be available until the next major release.