The "check_for_update"-webservice responses "update_needed=0" although the old release number is smaller than the current release number

here a log snippet:

2011-12-01 09:18:20.040 [info] <?xml version="1.0" encoding="ISO-8859-1"?>
2011-12-01 09:18:20.040 [info] <sos:order xmlns:sos="http://www.sos-berlin.com/scheduler"><sos:id>78817</sos:id><sos:state>100</sos:state><sos:initialState>100</sos:initialState><sos:jobChain>/CheckForUpdate</sos:jobChain><sos:job>/check_for_update</sos:job><sos:task>51151</sos:task><sos:inProcessSince>2011-12-01 07:18:11.202</sos:inProcessSince><sos:created>2011-12-01 07:18:10.843</sos:created><sos:priority>0</sos:priority><sos:webService>check_for_update</sos:webService><params><param><name>order_id</name><value>78817</value></param></params><CheckForUpdateAnswer><release>1.3.12.1285</release><new_release>1.3.12.1327</new_release><filename>scheduler_win32_update.zip</filename><os>Windows 7</os><os_install>win32</os_install><automatic_download>0</automatic_download><update_needed>0</update_needed></CheckForUpdateAnswer></sos:order>
2011-12-01 09:18:20.202 [info] OS: Windows 7
2011-12-01 09:18:20.203 [info] OS_INSTALL: win32
2011-12-01 09:18:20.203 [info] new_release: 1.3.12.1327
2011-12-01 09:18:20.203 [info] old_release: 1.3.12.1285
2011-12-01 09:18:20.203 [info] You run the latest release