W3C:

2008-10-09: The Web Applications Working Group has published the First Public Working Draft of Widgets 1.0: Updates. This specification defines a model to allow a widget user agent to locate and replace a widget resource with a new or different version of a widget resource. The updates model is designed to work both over HTTP and from local storage. For updates performed via the Web, the model makes use a simple XML documents that authors place on a Web server to indicate, amongst other things, where the next most suitable version of a widget resource can be retrieved from. It also defines a mechanism that allows authors to be notified of installation errors or success. This specification also describes how to renegotiate security policies when widgets are updated. Learn more about the Rich Web Client Activity. (Permalink)