On June 4, 2002, Apple Inc. released the fifth update to Mac OS X 10.1.x "Puma", Mac OS X 10.1.5. The build numbers vary: 5S60 is the build number for the original 10.1.5 update, whereas 5S66 is the build number following the installation of Networking Update 1.0, and 5T91 was a build released for certain Macs, noticeably iMac G4s.