Season 11 will be ending on the following dates and times:
North America: Friday, October 20 @ 5:00 p.m. PDT
Europe: Friday, October 20 @ 5:00 p.m. CEST
Asia: Friday, October 20 @ 5:00 p.m. KST
Season 12 will begin about three weeks afterward on the dates below:
North America: Thursday, November 9 @ 5:00 p.m. PDT
Europe: Thursday, November 9 @ 5:00 p.m. CEST
Asia: Thursday, November 9 @ 5:00 p.m. KST
Haedrig’s Gift
Barbarian : Immortal King’s Call
Crusader : Seeker of the Light
Demon Hunter : Natalya’s Vengeance
Monk : Uliana’s Stratagem
Necromancer : Trag'Oul's Avatar
Witch Doctor : Spirit of Arachyr
Wizard : Vyr’s Amazing Arcana
Conquests
On A Good Day/I Can't Stop: Level three Legendary Gems to level 65.
Boss Mode/Worlds Apart: Kill the following bosses at max level on Torment X or higher within 20 minutes of the start of the game.
The Thrill/Super Human: Reach Greater Rift Level 45 Solo without any Set items equipped.
Curses!/Stars Align: Kill 350 or more monsters in a Cursed Chest event at level 70 on Torment X difficulty or higher.
Years of War/Dynasty: Reach Greater Rift Level 55 Solo with the full bonuses of six of the following Class sets.
2.6.1 Patch Notes
https://us.battle.net/d3/en/blog/21115840