Blocking old versions of Subversion using WebDAV

I recently needed to block older clients from our corporate Subversion repository. It turns out merge history (which was introduced in SVN 1.5) isn’t stored property in older clients and can really be reliably counted upon from 1.6.6 and up. We had a requirement to mark 1.6 clients (earlier than 1.6.6) read-only, and deny earlier clients [...]