Hi,
you can install the DMG present on the wiki then do a manual upgrade.
this is the manual upgrade procedure:
execute the snom ONE Admin app and stop the service
substitute the executable contained in:
Applications/snomONE/BIN with the latest one downloaded from the wiki
open a terminal and execute those commands
cd /Applications/snomONE/bin/
chmod +x pbxctrl-darwin9.0-2011-4.2.1.4025
rm pbxctrl-darwin9.0
ln -s pbxctrl-darwin9.0-2011-4.2.1.4025 pbxctrl-darwin9.0
execute the snom ONE Admin app and restart the service