The Portals 4.1 specification was released in April 2017. It is available as a PDF here.
The Portals 4.0.2 specification (minor update) was released in October 2014. It is available as a PDF here.
Portals 4.0.1 is a minor update to the Portals 4.0 specification. The specification is available as a pdf.
Portals 4.0 is a major update to the Portals specification, which extends the API to better support PGAS languages. The specification is available as a pdf.
If you have any questions or comments, please contact the Portals 4 development team at firstname.lastname@example.org.