From FN

This is the second porting and usability article in our Tip Of The Month series; it takes a closer look at the decisions involved in porting application features. The first article, "Porting The Positive Experience," covered the basics of porting; the last article, "Optimizing The User Experience," will concentrate on user experience optimization and testing a large number of application versions.

From the document:

When porting applications to different platforms, some features may need to be added or dropped. An application that is optimal for one particular device may be too complex or too simple for another platform. Thus, it might not be a good idea to simply implement all the features in all the platforms. When ported downwards to simpler devices, an application often needs to be more focused on its core features in order to be usable. When ported upwards to more complex devices, device capabilities should be fully used by implementing additional features.

This requires flexibility from both the application engine and the developer. Be clear about the primary and secondary features of the application when making decisions about which features to support in certain platforms. For example, consider the typical owner of a Series 40 mobile phone and the owner of a Series 80 communicator. Each is likely to have different expectations as well as different needs for a particular application. If the same application is ported to both platforms, it may be too complex for a Series 40 user and too simple for a Series 80 user.

You'll have a better idea of what we mean when we examine how certain standard applications have been implemented in existing handsets. Let’s take a closer look at the implementation of the calendar functionality in different devices

Example: Calendar app - Series 60
In this calendar implementation, the additional screen size is used to enhance the application. Users can conveniently view future reminders, notes, and meetings at one glance. They can also choose a monthly, weekly, or daily view. All Series 60 devices can synchronize the calendar with a desktop computer. Additionally, some devices are capable of General Packet Radio Service (GPRS) synchronizing. Users can choose their own alarm tone, as well as if they prefer a daily, monthly, or weekly view by default. Additionally, there are different types of calendar events. Repeated calendar events are supported.
 
 
See http://www.forum.nokia.com/html_reader/main/1,,5597,00.html (269 KB PDF)