Duolingo GD from EN versions:

Trees:
v0: 2019-06-11  ? (Beta)
v0: 2019-11-02  ? (Beta)
v1: 2019-12-10, 34 Skills (34 Different lessons)
v2-v4: ?
v5: 2021-02-05, 107 Skills (107 Different lessons)

Paths:
1.0: 2022-09-10, 107 Skills (107 Different lessons) (69 Units)
1.1: 2023-09-10, 107 Skills (107 Different lessons) (70 Units)
2.0: 2023-11-14, 120 Skills (120 Different lessons) (78 Units)
2.1: 2024-05-01, 120 Skills (120 Different Lessons) (137 units)


tree_gd_en_v1_experiment
tree_gd_en_v2_experiment
tree_gd_en_v3_experiment
tree_gd_en_v4_new
tree_gd_en_v5_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.