Hi @sajarin,
Thank you very much again for your attentive answer.
Trying to go around the possibilities you offered, I finally managed to update to the new version of Label-Studio 1.12.1 (and Python 3.8). My problem has been solved then and I managed to export my annotations in COCO. I don’t know what worked with this new version but I am really grateful for your work.
Have a nice day,
Alice