KDE 4.4.5 packages for OpenSolaris are available. The primary mirror http://solaris.bionicmutton.org:10000 is known for dropping connections when download speed reaches ~100kB/s, so you might consider using the alternate mirror http://pkg.osladil.cz:30000.
As concerns changes from 4.4.4, there's nothing at all on the Solaris side, only the upstream changelog applies (a bunch of bug fixes).
Korona 4.4.5 is being uploaded to genunix.org - there are also no Solaris specific changes since Korona 4.4.3 (Korona skipped 4.4.4, as I was struggling with a bug in distro-constructor), apart from the KDE update also the following packages were bumped: amarok, boost, icu4c, konversation, libassuan, qimageblitz, qtcreator.
Several applications are starting and sometimes running slowly, most notably konqueror, this seems to be related to dbus - patches welcome.