For those who already have various servlets running it would help a lot to
explicitly mark the configuration data specific to open-xchange better, i.e.:

#------ open-xchange specific settings -----------------------------------------
#---------------------------------------------------------------------
java.net.preferIPv4Stack=true
[uri:/servlet/*]
worker=ajp13:localhost:8009

[uri:/servlet/webdav.contacts/*]
worker=ajp13:localhost:8009

[uri:/umin/*]
worker=ajp13:localhost:8009
# end of OX-specific settings

The rest of the file is the standard mod_jk2 workers.properties file anyways.