From https://www.twitch.tv/raphael_luba who is the other full time person working on Jai compiler:

The following things still need to get done before we can release Jai to a wider audience:

1) Support for referencing foreign symbols that aren’t functions (e.g. globals exported by a library)

2) Improve type table and context interoperability when Jai programs load static/dynamic Jai libraries.