There are 4 paid upgrade editions available, the Basic, Basic +1, Network and Network +1.
Basic Edition includes all the features listed hereWITHOUT the networking related features.
Basic +1 Edition comes with the same features as Basic Edition + 1 Year Free Upgrade.
Network Edition includes all the features listed hereAND the networking related features. Each purchase of Network Edition comes with 2 Client Licenses, which means you are allowed to install the software on 2 computers on the same network to be used by 2 different users. If you require more user licenses, e.g. for 9 users in your network environment, you may purchase 5 copies which in turn grant you 10 Client Licenses.
Network +1 Edition comes with the same features as Network Edition + 1 Year Free Upgrade.