After upgrading to version 4.5.1 I couldn't access the "Normal Display" admin page. (as well as the Floating Display page). It showed the following error:
Fatal error: dd_page_for_normal_display() [function.dd-page-for-normal-display]: The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition "DD_Sphinn" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition in /public_html/wp-content/plugins/digg-digg/include/template/dd-template-normal-display.php on line 63
My settings are preserved and everything shows right on the site, but I just couldn't change them from the admin pages anymore.
Now, I tried downgrading back to version 22.214.171.124 manually and the admin pages were back again. Currently, I upgraded again to the latest version, 4.5.1, and awaiting to see your response about that error.