Duolingo KO from EN versions:

Trees:
v0: 2016-02-04  ? (Beta)
v0: 2017-10-11, ? (Beta)
v1: 2018-05-17, 21 Skills (21 Different lessons)
v2: ?
v3: ?, 65 Skills (65 Different lessons)
v4: 2021-09-07, 94 Skills (94 Different lessons)

Paths:
1.0: 2022-09-10, 65 Skills (65 Different lessons) (51 units)
2.0: 2022-11-20, 94 Skills (94 Different lessons) (61 units)
3.0: 2023-09-10, 112 Skills (112 Different lessons) (72 units)
3.1: 2023-11-10, 112 Skills and 40 Stories = 152 Different lessons (73 units)
1.2: 2024-05-01, 112 Skills and 40 Stories = 152 Different Lessons (128 units)

tree_ko_en_v1_experiment
tree_ko_en_v2_experiment
tree_ko_en_v3_new
tree_ko_en_v4_existing

https://liuch.github.io/duolingo_courses_overview/
https://duolingo.fandom.com/wiki/Course_list
https://duolingodata.com/
https://duolingodata.com/oldtable.html
https://ardslot.com/duolingocrowns.html

Edited by Mat!/Ozone, 2024-05-02.