Soldiers start out as Privates (analogous to Rookies), where they have no class, and when they progress to Specialist (equivalent to Squaddie) they are assigned a class.
Like the base game, soldiers are divided into classes. To off-set the increased squad size, soldier classes have been made much more specific in their roles. The Super Skyranger upgrade will allow an additional 2 soldiers on alien base and Exalt HQ assaults, and an extra 4 soldiers on the final mission. Covert extraction missions are fixed at 4 + the covert operative. When defending the XCOM HQ the squad size is fixed at 6. It can be increased to 8 with Officer Training School upgrades as usual (though the prerequisites for the upgrades are a little different).
