Yesterday, a few videos of Jamala performing her winning entry 1944 before the regulation release date were brought to light. The EBU has now published an official statement regarding this issue:
https://www.facebook.com/EBU.HQ/posts/1049921921766891
The videos, uploaded on May 2015, showed Jamala performing her song 1944 during a concert which took place on May 18 last year. Although the song sounded a bit different from the Eurovision version, everyone thought it could have broken the rule which states that the songs performed at Eurovision mustn’t be made public until the 1st of September of the year before. However, it seems that if the songs haven’t been accessible by a wide audience, are granted permission to compete in the Eurovision Song Contest by the Reference Group.
Jamala won Eurovision 2016 with the support of a 50-50 combination of jury and televoting results.