Suprise update mechanics!
Just decided to hit update in launcher after 6 weeks, so I have no idea what it contains.

Major update of contact effects.
Ranged contact effects complete for all races.
Melee contact effects will be updated when I want to harm myself.

Normalized blunderbuss infantry HP to 7000 across factions.
Reduced thunderer per model HP to 66 from 70. Will probably reduce further, pending tests.

Minor fixes
Updated the UI groups for several (mostly dorf and empire) units.

Re-added T4 Engineer building requirement for brimstone gun gyrocopter
Added T3 smith requirement for steam gun gyrocopter; steam gun gyrocopter base building requirement is now T3 ranged military building.
Increased brimstone gun range from 100 to 175.
Reverted flame cannon gyro recruit time back to 3 turns.
Flame cannon gyrocopter base building requirement reduced to T4 ranged military building. Flame cannon gyrocopter can now be recruited at T4 as intended.
Removed one bad row in building_units_allowed that enabled flame cannon gyrocopters for empire.

See notes from an hour later

Deleted three duplicate rows
Corrected 3 calibration area entries that were set to 0.
Tweaked some penetration values for shotgun-style projectiles.
Slightly increased damage and explosive damage (1/0/1/3) for gyrocopter grapeshot. Increased targetting area and reduced projectile velocity further to compensate.
Increased upkeep and/or recruit costs for all gyrocopters.
Reduced T1 (steam/brimstone gun) and T2 gyrocopters (gyrobomber and flame cannon) recruit requirements and recruit time. Test phase pending.
Increased recruit requirements for cannon gyrocopter. Test phase pending.
Temporary fix for cannon gyrocopter's projectile VFX bug, as follows:
Grapeshot is now the primary projectile. The issue is shunted onto the much more visible standard shot.

Dorf missile infantry rebalanced around 100 dorf regiments. HP and missile damage reduced in accordance with higher numbers.
Most dorf infantry MD and HP has been increased.
Dorf melee infantry progression restored.
Fixed incorrect MA and MD values for Longbeards (Greataxes).
Increased both arrer boy variants to 100 orc regiments.

Gryocopter (Cannon) now can now select explosive grapeshot in battle.
Changed icon for deckgunners' multishot ammo toggle.

To-Do:

Find a fix for disabled projectile trails and explosion VFX.

Updated kv_rules for DLC15. Nothing special.