MechWarrior Online Developer Blog #4

Pilot and 'mech progression must have been a very popular subject in the last developer blog for MechWarrior Online, because blog entry #4 goes into further detail on the subject of "role warfare". There are even sketches of the 'mech efficiency and skill trees, as well as information on unlocking modules:
This is the basic layout of the tree for any of the 'Mechs or variants that we launch with (or when we initially introduce the base model and chassis of any brand new 'Mech). Players need to spend XP to unlock all of the upgrades on each tier in order to be able to access the next tier. The jump jet related upgrades on tier 4 would be removed for any 'Mech that doesn't have jump jets. In order to access Elite I, the player needs to not only unlock all upgrades on tiers 1-4 of this model, but they have to do the same for every initial variant. After they access and spend XP to unlock Elite I, tier 5 is then accessible for all initial variants. Elite II is accessed in a manner similar to Elite I. The player must have unlocked tier 8 on each of the initial variants.

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A Module is unlocked by gaining efficiencies in a particular BattleMech's Mech-XP Tree. When a single Tier for a given chassis is complete, the player earns 1 Player Point. Once a Module on the Pilot Skill Tree has been unlocked it produces modules. These modules are purchased as an item from the Store using C-Bills. If the player wishes to use the same module across multiple BattleMechs, they will have to purchase one for each.