You can update your Maps data for most of your devices through the Nokia Suite for Windows. On your Symbian device select the 'check for updates' button on Map loader menu of Nokia Maps app. On MeeGo device got to Maps Application > ManageMaps > Check for updates.
Windows Phone 7 users can download the updated maps data by opening the Nokia Drive app
The updated Maps have the following new improvements:
- Better maps for Tunisia, Senegal and Cyprus
- 1.86 million building outlines in Croatia
- Public transit in Hong Kong, Macau and Taiwan
- More Truck Attributes
source - Symbian Tweet