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Revision as of 10:07, 28 July 2007 by DenisDefreyne (talk | contribs)
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Appcast Brainstorming

The purpose of this page is to capture software updates practices in the wild, as one effort to codify practices currently used in the automatic update system called Sparkle.



Sites like,, and among others should be investigated and documented for object names and attributes.

Among common data in a software update changelog are changes or fixes, completed bugs, new features or modified behavior, and known issues. A version number is also typically supplied, but takes on many forms and is not always numeric.

Lastly, this work should be seen as compatible with hAtom, possibly as a prelude to a format that could be embedded as the payload of an hfeed object.

Work should be carried out on the Appcast Examples page.

Related Work

  • Downloads Brainstorming seems to have the same goal. Could these two pages be merged? DenisDefreyne 02:56, 28 Jul 2007 (PDT)
  • Hash examples has a section about hAtom integration. The example uses a "download" class, which contains a rel-enclosure link as well as a span with "md5" and "checksum" classes.

Sparkle-specific Appcast enhancements

Sparkle adds a few extra features to appcasts:

  • External release notes URL: used when the release notes are not included in the appcast itself
  • MD5 sums and DSA signatures: used for some extra security
  • Advanced version string: Sparkle determines the application version from the enclosure name, which is assumed to be; the advanced version string allows this convention to be overridden

hAppcasts should probably support these features as well.

The MD5 sum and DSA signature is specific for an enclosure. It is, however, not possible to add these extra attributes to a rel="enclosure" link; a larger "enclosure" microformat may be necessary (also see Hash examples).