Update 257 introduced a new combat system to Solaris. This article is aimed as a short overview to those familiar with the old system by noting the main differences. If you instead wish for a detailed explanation of the mechanics, look at this article: Combat Rework.
Instead of combat always having two sides, now any number of sides can participate in combat. For example, if players A, B, C are not allied with each other at all, they will form three combat groups.
Carriers travelling together will now correctly fight together.
Contrary to before, a weapons malus from an attacking specialist will now apply regardless of whether the specialist is on the largest carrier. Only the weapons malus with the largest amount will be applied (as before).
Combat now happens in proper rounds. In each round, the attack value of each group against each other group gets computed anew. The attack value is the number of enemy ships the group will destroy.
A groups attack value is limited by its ship number, e.g. a group of 4 ships will at most provide 4 attack.
Defender bonus works differently: besides gaining one extra weapons level, the defender bonus is applied after the weapons clamping, thus giving the defender extra attack in a low-ship scenario.