It exists in two major versions of 1887 and 1890.
The last major version, the Nova 4, was released in 1978.
Vopt I really like, which has always been at major version 8.
The second major public version was released a year later on 7 February 2008.
Currently there are a few major versions of the game.
A new major version is released about every 18 months.
If so little has changed, why the major version number increase?
Instead the next major version was to be the 213E, and the similar 213F.
The software hasn't seen a new major version since September 2007.
The third major public version was released two months later on April 21, 2007.