I just tested the update from Kokua 220.127.116.11998 (Jun 28 2013 17:19:24) to Kokua 18.104.22.168169 (Aug 21 2013 14:49:45) and it went well from old to new.
On older Kokua Viewers there will be a required update but, due a lack of correct notifications those will be directed to the Second Life Download web page. At that point a choice can be made to go ahead with the Second Life viewer install or exit the program and use this download link to install an updated Kokua.
This is not a conspiracy to force the Second Life viewer on anyone. The viewers involved do not support Server Side Appearance (SSA) and would be of limited use on Second Life grid.
THIS WAS MY DECISION. Please don’t grump about it to Second Life or their support group.