DevicesDetection plugin does not detect mobile phones (no replies)

piwik-2-1-0
settings | system check, everything is ok.
GeoIP (PECL) installed

Hello Coummunity,
I am very excited about PIWIK. works so nice.
I can track my first website....

when I activate the DevicesDetection plugin, the visitors | devices menu appears - but not track the mobile phones .
tested with iphone 4 , iphone 4s | ios 6 and ios 7 and safari.

What can be the reason please?

Thanks im advance!
S.