Duolingo AR from EN versions:

Trees:
v0: 2014-01-29, ? (Beta)
v0: 2014-05-09, ? (Beta)
v1: 2015-08-11, 31 Skills (31 Different lessons)
v2: ?
v3: 2020-05-29, 46 Skills (46 Different lessons)

Paths:
1.0: 2022-09-10, 46 Skills (46 Different lessons) (30 Units)
1.1: 2023-09-10, 46 Skills (46 Different lessons) (30 Units)
1.2: 2024-05-01, 46 Skills (46 Different lessons) (52 Units)

tree_ar_en_v1_experiment
tree_ar_en_v2_experiment
tree_ar_en_v3_experiment

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.