@DM2018 We're targeting general availability October 1st. That said, we just enabled the functionality to recognize an external user's license in their home tenant. This is in production, worldwide.
Does this mean that now if I share a canvas app with a guest user in my Azure AD, and that user has a PowerApps license in their own tenant, but not mine, she will be able to use the app? Because I tried this a couple weeks ago and I needed to provision an extra PowerApps license in my tenant.
I tested this functionality today within our multi-tenant environment and it appears to be working! I granted an "external/guest" user access to one of our canvas PowerApps and the person was able to access it successfully even though they were a "guest" within our tenant. I checked our Azure AD and the "guest" user does not have a license within our tenant. The "guest" user in question has a license issued to them from their home tenant, which appears to allow them access to my canvas PowerApp. I'm going to conduct further testing but early signs are promising.
@SS5 - Yes, as @DM2018 called out personal email accounts can be used by guests as long as they're licensed. Note, the personal email account must be a Microsoft Account.
The ability to share canvas apps with external users is now availabile in public preview! The documentation can be found here: https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/share-app#share-with-guests
The blog announcement is here: https://powerapps.microsoft.com/en-us/blog/share-canvas-apps-with-guests-in-your-organization/