Just upgraded to 1.2.3 Final. Smooth as can be (outstanding work devs!) Only glitch: when I went to top-level page, no widgets. I reinstalled the xml component of the dashboard and all was well. Hmmm….
That is normal.
The dashboard package replaces index.php, which is also overwritten during the upgrade process. Thus, you must reinstall the dashboard after any firmware upgrade in order to get the widgets back.