I have an active Marketing Cloud Journey that has a wait until June 15th date before participants receive an email. I need to update this date to June 1. Can I do that in the current version since I have not yet reached the Wait Until date or do I need to create a new version of this journey to change the Wait Until date?
You can only make changes to emails in an active journey.
If you create a new version of the journey, you will be able to update the wait activity, but keep in mind that all the contacts which have already been injected into the first version, will still have to wait until June 15th - there is no way to „transfer” them into the new version of the journey.
As an alternative, of course depending on the length and complexity of your journey, you could stop it completely (that way contacts that are already in the first version won’t continue the journey), create a new one with an updated date and inject all the contacts again.