Patch 2.0.0 (9 Apr 2013): Now deals approximately 16% more damage. The ability deals 25% additional damage if the target is affected by the Mercenary's Heat Signature. In addition, this ability now fires a slightly slower-moving projectile, ensuring that the Heat Signature effect will be properly recognized if Heatseeker Missiles is fired immediately after a Tracer Missile. Light 'Em Up no longer affects Heat Signatures applied by Tracer Missile.
Patch 1.2.0c (19 Apr 2012): This ability will now only gain extra damage from your additional stacks of Heat Signatures and will not incorrectly detect debuffs from other players.
Patch 1.2.0 (12 Apr 2012): Damage output has been increased by approximately 10%. Bonus damage dealt by this ability now correctly takes the number of your Heat Signatures on the target into account.
