Hi @Shona_Pennock and welcome to the julia discourse! I don’t follow Juno development (Juno being the julia IDE based on Atom) but reading through the thread linked to in the above post, it looks like julia 0.6.x releases are no longer supported:
Unless you have some old julia code you need to run on 0.6.4, I would highly recommend upgrading to the latest version of julia. It is actively supported and there have been many improvements. If you need to upgrade some old code to make it compatible with julia 1.x, then I recommend installing julia version 0.7. Running your 0.6 compatible code in julia 0.7 should give you useful deprecation warnings that will help you get the code up to date.