Try clicking this link in this blog post: "Upgrade instructions are available on BoonEx Trac." That takes you to the page http://www.boonex.com/trac/dolphin/wiki/6.1.5to6.1.6. Then click on the link "Dolphin 6.1 Patch 6" on that page. It leads to the wrong version of the upgrade (6.1.5.zip instead of 6.1.6.zip).