Hi, 

I want to use Python 3.10 or newer on Heroku. 
Heroku support suggests adding a 'runtime.txt' file to specify the Python version (https://devcenter.heroku.com/articles/python-runtimes). 
But when I zip the oTree project (using oTree 5.10), the 'runtime.txt' file gets removed. 

Any ideas how to resolve this? 
Thanks in advance!
Vincenz

This is not currently supported. oTree sets the Python version automatically (to 3.9 I believe). I am planning to release an update that changes this, but need to resolve some things first.

Thanks for the quick reaction!

I updated my heroku stack and have the following Build Error:

Build output
-----> Building on the Heroku-24 stack
-----> Using buildpack: heroku/python
-----> Python app detected
-----> Using Python version specified in runtime.txt
 !     
 !     Requested runtime 'python-3.9.16' is not available for this stack (heroku-24).
 !     
 !     For a list of the supported Python versions, see:
 !     https://devcenter.heroku.com/articles/python-support#supported-runtimes
 !     
 !     Push rejected, failed to compile Python app.

 !     Push failed
 
 Is this related? And can I resolve this?
 
 Best
 Hauke

Hi, please update otree and try again. I updated it so that it will install Python 3.12 on Heroku instead of 3.9.

and thanks for mentioning the issue.