In 2007, Apple effectively acquired the open-source CUPS project and in 2017 then decided to no longer develop CUPS under the GPL but rather the Apache 2.0 license for this widely used Unix / macOS / Linux print server. But at the end of 2019, the main developer of CUPS left Apple and, as a result of this public development of CUPS, apparently stopped. Fortunately, there is now a happy next chapter in the history of CUPS printing.
Apple decided not to continue with feature development on CUPS, and upstream feature development was effectively transferred to the OpenPrinting project. Michael Sweet, founder of CUPS and former Apple employee, presented the change at this month’s Open Printing Summit. Sweet admitted that Apple stopped actively developing CUPS when it left the company. But now he has been hired by Apple to apply important bug fixes from CUPS’s OpenPrinting fork to the Apple CUPS codebase for macOS. Apple CUPS will continue to see these bug fixes pulled from OpenPrinting CUPS but Apple is no longer interested in developing features on this print server.
OpenPrinting is now working on a CUPS 2.4 release with AirPrint / Mopria compatibility, OAuth 2.0 / OpenID authentication, pkg-config support, Snapcraft support, TLS enhancements, and a variety of other feature enhancements with now effectively the new CUPS upstream.
Plans for a CUPS 3.0 are even being developed with new server capabilities and other re-architectures of this long-running print server. More details on this renewed CUPS work via this slide game by Michael Sweet.
Since leaving Apple, Sweet has also developed the modern PAPPL printer application framework.