Plesk Panel 10.1.1 MU#9 – Product functional fixes – is available since Feb 15, 2011 through the Autoinstaller.
The Update delivers following bug fixes:
[*] Performance improvement: Apache more efficiently handles infinite loops.
[-] Atmail displayed the black page and the Javascript error:"Unable to get webmail password".
[-] Migration between Plesk servers failed as free disk space on a target server was not calculated correctly.