ISO: Proper way to pin Rasa + Rasa X versions

Anyone know of a good way of installing a specific version of Rasa, along with the compatible Rasa X version? I haven’t seen anything in the Rasa X docs that help as there’s no mention of compatible Rasa versions in the changelogs.

I’ve currently pinned Rasa 1.4.6 for my project, but I’m looking to install the corresponding Rasa X version and haven’t had any luck on 0.23.6 and 0.24.0

This is further complicated by having to have a different index url for Rasa X installations.