Zope 2.5 comes with builtin session support. An undoable storage is quite inefficient to store large amounts of rapidly changing data such as typical session data. Therefore, a RAM based storage, the so called TemporaryStorage, was integrated as container mainly for session data. Unfortunately, this storage does not implement versions. There is a high chance that using versions leads to a "TemporaryStorage does not support versions" exception, even if you are unaware to use sessions. At least, I made this experience using CMF. The patch lets TemporaryStorage ignore versions, when the environment variable ZOPE_TEMPSTORE_IGNORE_VERSIONS is set (to a non-empty value). This seams adequate for session data, as sessions seem orthogonal to versions. Be aware, however, that this may hit you. As some objects in the version are usually different from the corresponding objects outside the version, session information may be compatible with just one and not both of them. Download: <http://www.dieter.handshake.de/pyprojects/zope/TempStoreSession.pat> Dieter