Every tiddler has revisions. Every time a tiddler is changed, a new revision is created. Revisions are identified by an integer ID.

However, not all stores support revisions, so when a tiddler is changed, the existing single revision is replaced by the new one.

A list of revisions can be accessed at /bags/{bag_name}/tiddlers/{tiddler_title}/revisions and an individual revision at /bags/{bag_name}/tiddlers/{tiddler_title}/revisions/{revision}. Individual revisions are immutable.

In python code, retrieving a specific revision is done as follows:

{{{ tiddler = Tiddler(title, bag_name) tiddler.revision = 4 tiddler = store.get(tiddler) }}}

If the revision does not exist a {{{NoTiddlerError}}} exception is raised. If {{{revision}}} is not set, the most recent revision is retrieved.