The new PTR patch updated most of the spell data for Ulduar bosses, we can finally see what’s going on with boss changes in Ulduar. Most of these changes are from the hotfixes recently deployed on live servers.

Quote from Blizzard staff Achievement

Heroic: He Feeds On Your Tears – Defeat Algalon the Observer without any raid member dying to Algalon at any point during that raid lockout period.
Heroic: Observed – Defeat Algalon the Observer on Heroic Difficulty.

Ignis the Furnis Master
Ignis the Furnace Master

Molten now deals 1885 to 2115 fire damage. (Down from 4713 to 5287 damage)
Scorch (10) ground effect now causes 1885 to 2115 Fire damage every second to all enemies within 13 yards. (Down from 3770 to 4230 Fire damage)
Scorch (25) ground effect now causes 3016 to 3384 Fire damage every second to all enemies within 13 yards. (Down from 6032 to 6768 Fire damage)
Flame Jets now silences targets for 6 sec. (Down from 8 sec.)
Slag Pot (10) now deals 4500 fire damage every second for 10 sec. (Down from 5000 damage)
Slag Pot (25) now deals 6000 fire damage every second for 10 sec. (Down from 7500 damage)

Razorscale

Devouring Flame now inflicts 7863 to 9137 Fire damage. (Down from 8788 to 10212 damage)

XT-002 Deconstructor

Tympanic Tantrum now deals 10% damage every second for 8 sec. (Down from 12 sec.)
Searing Light now deals 2250 damage to all enemies within 8 yards. (Down from 2750 damage within 10 yards)
Gravity Bomb (10) now deals 11700 to 12300 damage to enemies within 12 yards. (Down from 17100 to 18900 damage and up from 10 yards)
Gravity Bomb (25) now deals 14625 to 15735 damage to enemies within 12 yards. (Down from 19000 to 21000 damage and up from 10 yards)
Heartbreak now increases damage by 40% and health by 150%. (Up from 35% damage and 45% health)

Iron Council

Overload (Stormcaller Brundir) range has been reduced from 30 to 20 yards.
Lightning Whirl (10) (Stormcaller Brundir) now deals 3770 to 4230 damage. (Down from 4713 to 5287 damage)
Lightning Whirl (25) (Stormcaller Brundir) now deals 5655 to 6345 damage. (Down from 7069 to 7931 damage)
Rune of Death (10) (Runemaster Molgeim) now deals 2750 Shadow damage every half-second. (Down from 3500 damage)
Rune of Death (25) (Runemaster Molgeim) now deals 3500 Shadow damage every half-second. (Down from 5000 damage)

Kologarn

Focused Eyebeam (10) now inflicts 2313 to 2687 nature damage. (Down from 2775 to 3225 damage)
Focused Eyebeam (25) now inflicts 3238 to 3762 nature damage. (Down from 4163 to 4837 damage)
Stone Grip Absorb (10) now absorbs 80,000 damage. (Down from 100,000)
Stone Grip Absorb (25) now absorbs 380,000 damage. (Down from 480,000)
Stone Grip (10) now deals 2925 to 3075 physical damage. (Down from 3700 to 4300 damage)
Stone Grip (25) now deals 3413 to 3587 physical damage. (Down from 5363 to 5637 damage)
Rumble now inflicts 3238 to 3862 Physical damage to targets within 7 yards. (Down from 4625 to 5375 damage to targets within 10 yards)
Stone Nova now inflicts 5550 to 6450 physical damage. (Down from 7400 to 8600 damage)

Auriaya

Auriaya

Auriaya

Strength of the Pack now increases damage done by 30%. (Down from 50%)
Terrifying Screech now causes enemies to flee in horror for 3 sec. (Down from 5 sec.)
Sonic Screech (10) now deals 60125 to 69875 Physical damage. (Down from 74000 to 86000 damage)
Sonic Screech (25) now deals 190000 to 210000 Physical damage. (Down from 231250 to 268750 damage)

Freya

Petrified Bark (Elder Stonebark) charges have been reduced from 80 to 60 in 10-Man, from 220 to 120 in 25-Man.
Stonebark’s Essence (Elder Stonebark) now increases physical damage dealt by Freya by 75%. (Up from 50%)
Brightleaf’s Essence (Elder Brightleaf) now increases Magic damage dealt by Freya and her Allies of Nature by 60%. (Up from 50%)
Iron Roots now deals 7800 to 8200 Nature damage every 2 sec. (Up from 5850 to 6150 damage)
Tidal Wave (Ancient Water Spirit) now deals 10175 to 11825 Nature damage. (Up from 7863 to 9137)
Pollinate now heals the Guardian Lasher for 15%. (Down from 25%)
Bind Life (10) (Misguided Nymph) now heals for 9250 to 10750 health every second. (Down from 13875 to 16125 health)
Bind Life (25) (Misguided Nymph) now heals for 13875 to 16125 health every second. (Down from 27750 to 32250 health)

Mimiron

Proximity Mines now deals 15000 Fire damage. (Down from 25000 damage)
Emergency Mode (Hard Mode) now increases damage and health by 30%. (Up from 25%)

General Vezax

Shadow Crash now reduces mana costs to spellcasters by 70%. (Old – reduced mana costs for everyone, possibly a wording change to clarify that it only affects mana and not rage/energy/etc..)
Profound Darkness now inflicts 750 damage to all enemies, and increases Shadow damage taken by 10% per application. (Up from 500 damage)

Algalon

Algalon

Algalon

Cosmic Smash (10) now deals 41438 to 43562 Fire damage. (Up from 35613 to 41387 damage)
Cosmic Smash (25) now deals 53625 to 56375 Fire damage. (Up from 46250 to 53750 damage)
Black Hole Explosion now deals 16088 to 16912 Shadow damage. (Up from 14725 to 16275 damage)
Quantum Strike now deals 34125 to 35875 Physical damage. (Up from 23750 to 26250 damage)