#1 by MMMZZZ

When I click the link (see attachement) to download the csv data file from the Heroku Otree SessionData page from a web browser, instead of the requested CSV I get a page with the following error:

"Env var OTREE_REST_KEY must be defined to use REST API"

How and where do I define OTREE_REST_KEY to use REST API?  I just want to download my session data.

• Screenshot 2026-01-08 122820.png

#2 by Chris_oTree

Hi, thanks for reporting! I've fixed the issue; try updating otree with `pip install otree --upgrade`.

#3 by MMMZZZ

Thanks!  I just use the Studio online on oTree Hub.  Can it be reinstalled for the online version?

#4 by Chris_oTree

For oTree Studio, it automatically downloads the latest version of otree when you first deploy, then keeps that version. So you would need to trigger a re-build, or recreate the app, etc.

#5 by MMMZZZ

Great!  Thank worked.  Thanks!