Duolingo GA from EN versions:

Trees:
v0: 2014-03-17  ? (Beta)
v0: 2014-08-25  ? (Beta)
v1: 2015-01-16, 64 Skills (Different lessons)
v2: 2018-09-26, 66 " " "

Paths:
1.0: 2022-09-10, 66  Different lessons (42 Units)
1.1: 2023-09-10, 66  Different lessons (43 Units)
1.2: 2024-05-01, 66  Different lessons (75 Units)

CEFR:
1.0: 2024-04-01, 66  Different lessons (CEFR A1) (43 Units) (Beta)
1.1: ? Experimental (CEFR A1) (Beta)


tree_ga_en_a1_0_existing
tree_ga_en_a1_0_new

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.