Below you can see the changelog, which have been made on 5.4.8 for last month, from 19.01.16 to 18.02.16:

Status: applied for all realms.

General:

- Fixed a bug when bonuses of character or a guild didn't affect on bonus to the reputation for execution of daily quests.
- Final part of optimization of the core, server delay had been reduced by 15-20%, now it almost doesn't increase even when there is peak online and massive battles.
- Fixed a visual bug when player up to 20 lvl was appeared in a taxi without transport.
- Implemented work of the new transport system, now mobs will be correctly displaying on the transport like the players.
- Fixed a number of exploits when players were able to save spells from the previous specialization by changing of it.
- Implemented display of the information about bonus reputation of factions.
- Implemented work of quest chain on getting Fel Flame for Warlocks.
- Started implementation of quest chain on getting the legendary cloaks (Part 2 of 5)
- Fixed issuance of achievements http://www.wowhead.com/achievement=1693, http://www.wowhead.com/achievement=971, http://www.wowhead.com/achievement=3478 (title for the horde) at special NPC, if all criteria are completed, but the achievement was not issued automaticaly.
- Fixed an exploit with getting rights of a gould master.
- Added check targets for all pets.
- Rewrote regeneration of energy players.

- Fixed 7 reasons of server crash.

Instances and raids:

Siege of Orgrimmar:

- Rewrote loot from the trash mobs.

- Sha of Pride:
* Added loot.
* Fixed an issue when the boss was not saved in the dungeon progress.

Throne of Thunder:

- Fixed issuance of the reputation with Shado-Pan Assault after killing bosses.
- Rewrote loot from the trash mobs.

- Horridon:
* Fixed a bug when players were able to get attack speed from the aura of Dire Call.

- Ji-Kun:
* Fixed the appearance of feathers Ji-Kun.

- Primordius:
* Improved mechanics mutations.
* Fixed the ability http://www.wowhead.com/spell=136216/caustic-gas.
* Fixed the ability http://www.wowhead.com/spell=136218/acidic-spines.
* Fixed the ability http://www.wowhead.com/spell=136228/volatile-pathogen.
* Fixed the ability http://www.wowhead.com/spell=136245/metabolic-boost.
* Fixed getting of mutations by player.

Instances and raids, other:

- On heroic mode and challenge mode implemented the following dungeons: Shado-Pan Monastery, Temple of the Jade Serpent, Stormstout Brewery, Gate of the Setting Sun, Mogu'shan Palace, Siege of Niuzao Temple.
- Fixed leaving out a dead body at wipe on bosses.
- Fixed display of the timer during the passage of the dungeons in the challenge mode.
- Rewritten and returned the loot in Scarlet Monastery а normal level of complexity.
- Fixed an exploit with using the Lana'thel's bite outside the IC.
- Implemented the work of individual scenarios (eg for the chain on Fel Flame).

Items:

- Fixed work of http://www.wowhead.com/item=94295/primal-egg.
- Fixed a bug when additional bonuses influenced to http://www.wowhead.com/item=3475/cloak-of-flames.
- Fixed an exploit when low lvl enchants incorrectly copied on the maximum level and gave more bonuses than actual enchants.
- Fixed a bug when summons from http://www.wowhead.com/item=89301, http://www.wowhead.com/item=89302, http://www.wowhead.com/item=89303, http://mop.wowroad.info/?item=89224 items, were able to move and attack players.
- Fixed an exploit with http://www.wowhead.com/item=93180/re-configured-remote.
- Fixed http://www.wowhead.com/item=79769/demon-hunters-aspect.

Cross server:

- Fixed the command .spectate player .
- Fixed a number of problems when players weren't be able to register on the cross server.
- Fixed a number of reinforcements at the start of Alterac.
- Fixed a bug in the work of http://mop.wowroad.info/?spell=34709 in the arena and stealth effects.

Spells and talents:

Druid:

- Fixed an exploit when was able to bug http://cata.wowroad.info/?spell=81274.
- Fixed a bug with the influence of different bonuses on http://mop.wowroad.info/?spell=52752 and healing amount.
- Fixed an exploit with operation http://www.wowhead.com/spell=78675/solar-beam and the like area triggers.
- Fixed bonus of http://mop.wowroad.info/?spell=138216 set.
- Fixed work of http://www.wowhead.com/spell=17007/leader-of-the-pack.

Shaman:

- Fixed range / size for http://mop.wowroad.info/?npc=53006.
- Fixed work of http://www.wowhead.com/spell=117012/unleashed-fury for http://mop.wowroad.info/?spell=51730.
- Fixed a bug when because of it players were resurrected incorrectly after death + Fixed the glyph.
- Fixed a bug when because of http://www.wowhead.com/spell=55447/glyph-of-flame-shock players were resurrected incorrectly after death + Fixed the glyph.

Death knight:

- Several fixes to the runes mechanic, should be a little better by visually.
- Fixed a bug when sometimes http://www.wowhead.com/spell=114556/purgatory talent could not work.
- Fixed work of http://www.wowhead.com/spell=51462/runic-corruption.
- Fixed a bug when the ghoul while under http://www.wowhead.com/spell=63560/dark-transformation, continued to create charges of http://www.wowhead.com/spell=49572/shadow-infusion by http://www.wowhead.com/spell=47541/death-coil damage.
- Fixed a bug when http://www.wowhead.com/spell=47481/gnaw didn't replace http://www.wowhead.com/spell=91797/monstrous-blow at using http://www.wowhead.com/spell=63560/dark-transformation.
- Fixed http://www.wowhead.com/item=104048/g...nerative-magic.
- Fixed http://www.wowhead.com/spell=50977/death-gate in DK location.

Hunter:

- Fixed a bug with summing periodic damage from http://www.wowhead.com/spell=53301/explosive-shot.
- Fixs to the mechanics of http://www.wowhead.com/spell=13809/ice-trap.

Mage:

- Fixed http://www.wowhead.com/item=104106/g...f-condensation and analogues.
- Fixed a bug with the double damage from http://www.wowhead.com/spell=11366/pyroblast spell.
- Fixed a bug when the effect of http://www.wowhead.com/spell=44549/brain-freeze disappeared immediately after casting.
- Rewrote work of http://www.wowhead.com/spell=76613/mastery-icicles.
- One more attempt to fix a bug at interaction of http://www.wowhead.com/spell=84714/frozen-orb + http://www.wowhead.com/spell=118/polymorph.
- Fixed a number of exploits with http://www.wowhead.com/spell=108978/alter-time spell.

Warrior:

- Fixed interaction of http://mop.wowroad.info/?spell=133278 and http://mop.wowroad.info/?spell=133277.
- Fixed a bug, when http://www.wowhead.com/spell=118000/dragon-roar does not work properly after the previous fixes.
- Fixed the damage of http://www.wowhead.com/spell=46968/shockwave spell.
- Fixed a mechanic of getting furious at the parry.
- Fixed http://www.wowhead.com/item=43396/gl...curdling-shout.
- Fixed http://www.wowhead.com/item=43395/glyph-of-mystic-shout.
- Fixed http://www.wowhead.com/item=104138/g...e-weaponmaster.

Warlock:

- Implemented work of quest chain on getting Fel Flame and the impact of fire on the skills.
- Fixed a replacement of spell http://www.wowhead.com/item=43395/glyph-of-mystic-shout when entering in http://mop.wowroad.info/?spell=148968.
- Fixed work conditions of spell http://www.wowhead.com/spell=108558/nightfall.
- Implemented the correct transfer of the player using http://www.wowhead.com/spell=111771/demonic-gateway.
- Fixed spell school for http://www.wowhead.com/spell=103964/touch-of-chaos, http://www.wowhead.com/spell=129347/chaos-wave, http://www.wowhead.com/spell=124913/doom.
- Fixed http://www.wowhead.com/item=42459/glyph-of-felguard.
- Fixed a visual part for http://www.wowhead.com/spell=170619/malefic-grasp.

Priest:

- Fixed a bug when the negative effects were able to influence incorrectly on http://www.wowhead.com/spell=17/power-word-shield and then absorption disappeared.
- Fixed a bug when the effect of http://www.wowhead.com/spell=55686/glyph-of-inner-fire didn't disappear.
- Fixed work of http://www.wowhead.com/spell=138302/golden-apparition.
- Fixed using of http://www.wowhead.com/planner spell.
- Fixed visual display of http://www.wowhead.com/spell=78203/shadowy-apparitions.
- Fixed a number of checking for http://www.wowhead.com/spell=62618/power-word-barrier.

Monk:

- Fixed interaction of http://www.wowhead.com/spell=116847/rushing-jade-wind and http://www.wowhead.com/spell=115070/...e-wise-serpent, with a number of hunter spells.
- Fixed a formula for spell http://www.wowhead.com/spell=115310/revival.
- Fixed the influence of http://www.wowhead.com/spell=117907/...of-the-serpent to http://www.wowhead.com/spell=116847/rushing-jade-wind.
- Added a limit of targets for http: //vvv.vovhead.kom/spell=107270/spinning-krane-kisk.
- Fixed http://www.wowhead.com/spell=146950/...eted-expulsion.
- Fixed http://mop.wowroad.info/?spell=120482.
- Fixed promlems with cd on http://www.wowhead.com/spell=115399/chi-brew.
- Rewrote work of http://www.wowhead.com/spell=115080/touch-of-death.

Paladin:

- Fixed mechanic of talent http://www.wowhead.com/spell=114039/hand-of-purity.

Rogue:

- Fixed mechanic of http://www.wowhead.com/spell=31224/cloak-of-shadows.
- Fixed http://www.wowhead.com/spell=114015/anticipation with http://www.wowhead.com/spell=1752/sinister-strike.

Spells and talents, others:

- Fixed display of information about the loss of control.
- Fixed visual bugs while effects of disorientation and strike.
- Fixed a bug when http://mop.wowroad.info/?spell=147277 could be used outside of Pandaria.
- Fixed updating of the current energy status, using the spells that simulate death.
- Implemented more correct work of charge effects.
- Rewrote work of spells with the effect of the resurrection.
- Fixed http://www.wowhead.com/spell=126393/eternal-guardian.

- All Data Base fixes (quests, creatures, loot etc) you can look at this section (from 19.01.16 tо 18.02.16), with messages from Herald.

Don't forget to clear the cache of the game after the update.