I really like memoQ's versioning features, and I use the X-Translate function fairly often when a document I'm translating has been updated or a new version comes sometime later. However, I don't keep documents in my projects forever. I use "container projects" for particular clients or subject domains so that I don't have to keep reattaching the same translation memories, terminologies and LiveDocs corpora and various light resources (non-translatables, autocorrect lists, segmentation rules, etc.) all the time. These can get rather full, so I send my old translations off to a LiveDocs corpus after a while. And then if a new version of a document shows up, well... I'm sort of out of luck if I want to use the X-Translate function with the previous version.