Promises with async shiny on shiny server open source

I've built an app that leverages promises from the async shiny dev repo. It runs great locally on a mac, but it doesn't display any output from the async portion of the app when deployed on shiny server open source (ubuntu ec2 instance with 4 cores). Do promises only work on shiny server pro?

Found an answer on my own! Thankfully it does work on open source! The issue was with ubuntu and the httpuv package, which needs to be updated with a special linux dependency before installing the async shiny dev package from github.