The "old" namespace is a collection of pages imported from our previous mediawiki wiki. Use these pages as a last resort if you can't find anything in the main wiki.
As pages get checked and we are confident there is no longer a need for these old versions, they will be deleted. You can still access the old versions by adding &do=revisions to the page name in the URL. The deleted pages are listed here.
Click the links below to access the revision history. Otherwise do a search to find the up-to-date information in the main area of the wiki.