The Network Servers were sold exclusively with AIX, in a version called "AIX for Apple Network Servers" with some Apple-specific features, like AppleShare services, added; two revisions, 4.1.4 and 4.1.5, exist. Apple's own Unix variant A/UX had already been discontinued and does not support the PowerPC. Due to their AIX OS and hardware similarities, the Network Servers are mostly binary compatible with the RS/6000 series.