will applications written for n73 work on n95,n96 n82m n79 ?

[matx1212]

will applications written for n73 work on n95,n96 n82m n79 ?

[wizard_hu_]

Mostly yes, newer S60 3rd edition devices are generally backward compatible with older ones. However it also depends on the API-s used by the given application. API-s originating from various plug-in packs may cause incompatibility.
You can find some related papers in the Docs section above, then Documentation, Symbian C++, Compatibility.

[Symbian_Neil]

Depends on the application as to what APIs it is using, etc. So only you can answer your own question coz here only you know your applicaion and what its doing and what its using ;)
Release notes might sometimes give you hints on what APIs are depreciated.