Xcraft project with the combat system version 1 was released In 2009, a little bit later  combat system 2 was appeared. Battle systems 1 and 2 were "stacked". This means that a group of units of the same type was actually considered as one large unit of this type and when the group got damage for the amount of armor of 1 ship in the group, 1 unit died.
For example, one cruiser has an armor of 2500, and a group of 100 cruisers has a total armor of 250,000. When a group of damage is received in 2500 by one or more firing, 1 cruiser dies, 99 cruisers remain in the group.

In 2011, the battle system version 3 was presented, where the stack system was replaced by a system in which the armor of each unit in the group was calculated separately, and any unit  died because the shots seldom occurred on the same unit.
For example, one cruiser has an armor of 2500, and a group of 100 cruisers has a total armor of 250,000. When a group receives the damage 2500 by one shot, the probability of death of 1 cruiser is 1 to 100 (rarely both shots fall into the same cruiser).

To balance this, a "concentration" was introduced. This is when the enemy tries to attack the weakest unit in the group to inflict at least some damage. Until today concentration worked in combat system 4 partially, but now we introduce it for all units as a basic rule.

From now on, attacking a group of units of the same type, attacking forces try to focus the shots on the same units in order to destroy the maximum number of enemy units.
The concentration is 75%.

For example, without concentration, if 10 000 battleships attack 10 000 needle trees with equal technology, the losses of battleships are equal to 0 with complete destruction of trees.
With the concentration introduced today, the loss of battleships will be 8000-9000 of battle experience (up to 500 pieces).

Innovation is necessary to counter the strategy of "rollers" from units of the same type which were almost immortal without concentration. Now there will be more motivation to select and combine fleets.

The speed of the shots of the Spore Colonies is doubled.