The project extensions described in the dialog have actually been available for some time, primarily for those who wanted an alternative to Apple’s Photos Print Products. The announcement came in the form of a dialog that appears when selecting any of the File > Create options in Photos: The dialog notifying Photos users to switch to third-party extensions to create print products With the recent update to macOS 10.13.6, Apple quietly announced that it would no longer offer Photos Print Products after September 30, 2018.
Since 2002, iPhotos and Photos on the Mac have always offered the ability to create books, cards, and calendars, as well as to order prints of favorite photos.
