Back when version 0.31 was released, a new namespace was created on the wiki (so that the existing content from 40d and earlier could be preserved), and it was named "DF2010" because that's presumably what people had been calling it up until then. Since version 0.34 is not save-compatible with earlier versions, it also gets a new namespace on the wiki, but since it hasn't had a "nickname" like 0.31 did, we don't know what to call it, so the wiki's been temporarily locked until we decide (so people don't start modifying the existing pages).
Ideas that have been proposed on IRC:
* DF2012 - No better than DF2010, really.
* FEB2012 - Emi's idea. I don't care for it
* V34 - obvious, but has the potential issue that Toady might release 0.35 (or later) and maintain save compatibility, thus necessitating renaming it in the future.
* Rel4 - Going by savegame compatibility, versions 0.21.93.19a thru 0.23.130.23a (the 2D ones) were "release 1", 0.27.169.32a thru 0.28.181.40d were "release 2", and 0.31.01 thru 0.31.25 were "release 3", so version 0.34.01 is the first of "release 4".
Along with choosing a name for the new version's namespace, it's also an option to rename the existing namespaces. 23a and 40d are well-known enough that they can probably stay as-is, but "DF2010" could really stand to be changed to something better.
Any suggestions are welcome - the sooner we decide, the sooner the wiki can be re-opened to editing.