Upgrading from 1.4 branch to 1.5 branch is the single most useful thing you can do, however, it can be prone to things going wrong. If you follow the instructions in the release notes and the UPGRADE file, then you *should* be fine, but of course, make a backup (both of the database, and the filesystem, e.g. images) first, and be prepared to roll back to this and start over.
Particular caveats include where the old MediaWiki installation is using non-UTF8 encoding for text. MediaWiki 1.5 and later use UTF8 for text storage, regardless of other factors. You may need to customise and use the partial upgrade1_5.php script - be aware that this is not documented, and will need modification for your environment.
In direct response to the question; the "correct" upgrade methods will not cause a loss of data, but as with all things, caution is advised, and a backup is near-essential.
Rob Church
On 19/01/06, John Bidder member@highlanddrive.wanadoo.co.uk wrote:
I've never done an updgrade of Media Wiki. I'm on 1.4.7 and heading up to 1.5.5
I'm looking for reassurance from people that the contents/images etc of the Wiki will be left intact if normal upgrade/installation methods are used. I can't imagine for a moment that upgrading will make data disappear but lack of experience makes me cautious. Thanks John _______________________________________________ MediaWiki-l mailing list MediaWiki-l@Wikimedia.org http://mail.wikipedia.org/mailman/listinfo/mediawiki-l