35029 is an older version released on 2011-12-22.  The I0coin-qt client was just released a few weeks ago.  It's based on a much more recent version of bitcoin.  As far as I know it's not been posted anywhere but this forum (post # 1652).  Someone probably should post it on http://i0coin.bitparking.com/.  There shouldn't be any reason not to upgrade as long as the -qt version mines ok.  We could get another fork come Oct-2012 if 51% of miners are not using the new -qt client.  That should be plenty of time.