and it not 4.1 17.12.02 but only 17.12.02.
As explained if these posts, we changed our release name and we are using a semantic way based on released date.

https://www.recalbox.com/blog/en/post/blog-2017-11-01-recalbox-17.11.02/
https://www.recalbox.com/blog/en/post/blog-2017-10-15-after-4.1/