Duolingo RU from EN versions:

Trees:
v0: 2014-02-01  ? (Beta)
v1: 2015-11-02  ? (Beta)
v2-v7: ?
v8: 2017-03-10, 79 Skills (79 Different lessons)

Paths:
1.0: 2022-09-10, 79 Skills (79 Different lessons) (51 Units)
2.0: 2023-03-01, 95 Skills (95 Different lessons) (61 Units)
2.1: 2023-09-10, 95 Skills (95 Different lessons) (62 Units)
2.2: 2024-05-01, 95 Skills (95 Different Lessons) (108 units)


tree_tree_ru_en_v6_experiment
tree_ru_en_v7_new
tree_ru_en_v8_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.