# 20.3.
You can no longer revisit sectors.
Traders and techlabs can now be "freed" by destroying all enemies in the sector. Afterwards you can access them directly from the galaxy map.
Added 7 new AI races to the game.
The number of AI races in a galaxy now depends on the galaxy size.
The nebula types you encounter in a sector now depend on the hue of the background image.
Replaced the attribute colors.
You can no longer leave the editor without a CC.
Note: Some of these changes will not affect existing saves.