The only working library for celery in php is gjedeer/celery-php
and it doesn't support redis as backend.
https://github.com/gjedeer/celery-php/issues/9
Do you have any idea to get results in php?
I think you misread the ticket: The project did not support redis back in 2013 but added support in 2014 (comment). The main readme in the repo you liked also has examples on how to connect to redis.