Hi Thomas,

Horizon team working on adding django3.x support in horizon.
A series of patches to add django3.x support is already up [1] and We recently merged a non-voting job to test
django3.x which is failing right now[2]. The main issue we are facing in migration to django3.x is horizon
using django-pyscss which isn't compatible with django3.x although we have some workaround to fix it[3]
but it is not the right way. So I tried to contact the django-pyscss maintainer, but they didn't respond.
Then we plan to use an alternative of django-pyscss i.e. django-sass-processor.

Update on django-sass-processor: Me and radomir from horizon team worked on adding django-sass-processor
support in horizon[4]. As far our testing it works fine with horizon but horizon default theme doesn't work with it