Yes, we focused on Python 2.x support for initial release. I'm afraid we haven't even tried Wagtail on Python 3 yet. Having said that, at Torchbox (where Wagtail originated) we have a general if somewhat vague principle that - as responsible Python developers - we should support the adoption of Python 3, so 3.x support is certainly a goal for the project.

If anyone has time to test Wagtail on Python 3 and report any problems to https://github.com/torchbox/wagtail/issues that will accelerate the work!