Minimum system requirements will be posted as development of MapForge v1.0 nears completion. It’s too soon to give many details at this point, but a minimum screen resolution of 1280×768 is quite likely (this is not intended for netbooks!).
Other requirements should be relatively modest, and I expect that MapForge will be usable on a typical 3-4 year old PC. A good amount of RAM will probably be more important than having the latest-and-greatest CPU.
MapForge will be usable offline. The only time you’ll need internet access is to register new Add-Ons, download free software updates, and to purchase Add-Ons. If you happen to be online when you launch the app, you will automatically be informed of new software updates and Add-Ons as they become available.
Supported operating systems will be Mac OS X and Windows (possibly XP through Windows 10). Linux users might be able to run the software using WINE or Virtualbox.