Nokia N97 SDK release note is reassuring, making it look like their SDK add-on is pretty backwards, forwards and device compatible. Wouldn't expect anything less, considering Nokia used to own S60 platform. However Samsung release note especially says:
NaviSensor provides an alternative to the S60 5.0 Sensor Framework API.The very first non-Nokia S60 SDK extension is fragmenting the Symbian OS platform. Even thought Samsung i8910 is a delicious device, I think this is the beginning of a troublesome developer friendship (walking into fog).