Meta question: is there a place in the wikipedia for these issues? (Yes, http://www.wikipedia.com/wiki.phtml?title=wikipedia:PHP+script+bug+reports ugh, what a horrible URL. )
Meta meta question: is a wiki appropriate for defect tracking? (not answered)
The history of pages has been amputated when changing to the new software, in other words, changes made before the new PHP software are not accessible. I see two problems with this:
1) Lost authorship.
2) Lost changes.
1) is the problem that the revision history used to contain the author information for the documents. I understand that it is a requirement of the Gnu FDL that the author information be retained so that it can be reproduced as needed under the terms of the license.
2) is more obvious, but perhaps less problematic. In many cases you may say "so what", but the fact is that there may have been useful content in older revisions (I have browsed the older revisions in order to understand the creation process of a document or gain insight into some debate). This content has now been thrown away. What is the policy on keeping older versions? Is it "keep all of them" or "only keep revisions when it is convenient, in particular if changing the software destroys all older revisions then that's fine"? Don't forget that the software will change again and again over the lifetime of the wikipedia. I would say it behoves wikipedia to maintain a storage format that is largely independent of the software (even if that storage format is not the one used by the software, it could be an export format for example).
Sorry to go on about 2) so much, but it strikes me that the current attitude is a little immature. The current attitude as I see it is one of "changing software is simple; maintaining a database is not our concern; user requirements are only superficially important".
I think 1) (the authorship problem) needs addressing. What is intended?
Cheers, drj