ICal

Calendar (macOS)

Calendar running on OS X Yosemite
Developer(s)	Apple Inc.
Initial release	September 10, 2002; 14 years ago (2002-09-10)
Stable release	9.0 / August 19, 2016; 4 months ago (2016-08-19)
Operating system	macOS
Type	Electronic calendar
License	Proprietary
Website	www.apple.com/osx/apps/#calendar

Calendar (iOS)

Calendar in iOS 7 on iPad
Developer(s)	Apple Inc.
Initial release	June 17, 2007; 9 years ago (2007-06-17)
Stable release	8.3 (12F69/12F70) / April 8, 2015; 20 months ago (2015-04-08)
Operating system	iOS, watchOS
Type	Electronic calendar
License	Proprietary
Website	iOS and iCloud Calendar

Calendar is a personal calendar application made by Apple Inc. that runs on both the macOS desktop operating system and iOS mobile operating system. It offers online cloud backup of calendars using Apple's iCloud service, or can synchronise with other calendar services, including Google Calendar and Microsoft Exchange Server.

The macOS version was known as iCal before the release of OS X Mountain Lion in July 2012. Originally released as a free download for Mac OS X v10.2 on September 10, 2002, it was bundled with the operating system as iCal 1.5 with the release of Mac OS X v10.3. iCal was the first calendar application for Mac OS X to offer support for multiple calendars and the ability to intermittently publish/subscribe to calendars on WebDAV servers. Version 2 of iCal was released as part of Mac OS X v10.4, Version 3 as part of Mac OS X v10.5, Version 4 as part of Mac OS X v10.6, Version 5 as part of Mac OS X v10.7, Version 6 as part of OS X v10.8, Version 7 as part of OS X v10.9, Version 8 as part of OS X v10.10 and OS X v10.11, and version 9 as part of macOS v10.12.

Apple licensed the iCal name from Brown Bear Software, who have used it for their iCal application since 1997.