As outlined in a previous post these standards are offered to meet the challenge of exchanging contact information and exchanging calendar events in a form people may use to add to their address book or calendar applications. Other uses such as interchanging addresses between databases, whilst possible with vCard and iCalendar, are beyond the scope of these challenges, but could form the basis for further challenges for the open standards process.
This means both vCard and iCalendar are now in the implementation phase and you are encouraged to report issues with adopted standards on the Standards Hub.
Both the vCard and iCalendar formats have been in widespread use for more than 10 years, and most applications follow Jon Postel’s Robustness principle by ignoring fields and values they don’t understand or are incapable of processing. This means in practice publishers should not rely upon extended or unusual fields being available to all users in every circumstance.
The versions selected by the Board are specified and maintained by the Internet Engineering Task Force who ratify a number of commonly used extensions. The versions are largely backwards compatible with previous versions produced and consumed by a very wide range of applications. Older versions of vCard and iCalendar map directly to the standard versions with one notable exception: both vCard version 4.0 and iCalendar 2.0 require a Mandatory UID field to assist when processing the same contact or event more than once. The UID should be a persistent, resolvable identifier which we suggest should be the URL of a Web page where the contact information is published.
We would like to thank everybody who contributed to the process, in particular members of the open standards data panel and David Thewlis of CalConnect. CalConnect are developing further standards based on vCard and iCalendar to define protocols for the interchange of contact information and organising times for events and other issues, including support for non-gregorian calendars.