Blizzard have announced the return of the XP buff, as Wrath Classic players will be receiving a 50% buff starting today!
XP Buff (Source)
The roads in Northrend are icy and fraught with danger. To help you prepare for the Call of the Crusade content update, players will get the benefit of the Joyous Journeys experience buff*, which will increase experience gains by 50% for all players through level 80! It’s a great time to finish leveling a character, create a new one, or invite friends to join you in your adventures.
Players can also visit any innkeeper in the capital cities and Dalaran to turn the experience buff off or on. The Joyous Journey’s experience buff will be available from 23 May through 19 June 2023.
*Experience buff not available in modern World of Warcraft® or World of Warcraft® Classic Era.