Duolingo CY from EN versions:

Trees:
v0: 2015-10-08, ?  (Beta)
v0: 2016-01-26, ?  (Beta)
v1: 2016-07-02, 51 Skills (51 Different Lessons)
v2: 2019-09-11, 118 Skills (118 Different Lessons)
v3: ?
v4: 2022-04-18, 107 Skills (107 Different Lessons)
v5: ?

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: 2024-02-02, 112 Skills (112 Different Lessons) (73 units)
2.1: 2024-05-01, 112 Skills (112 Different Lessons) (128 units)

tree_cy_en_v2_experiment
tree_cy_en_v3_experiment
tree_cy_en_v4_experiment
tree_cy_en_v5_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.