There’s an update on their Facebook and Discord. I’ll paste the text, but here’s the link so you can also see all the pictures they posted alongside it.
"I hope you all had fun with the Tech Alpha for FS 2024. We STILL have not had ANY dev access and wont get the SDK until the end of the month, however, we want to let you know we’re getting ready to release the JetStar into Early Access in a THIS week!.
OMG Early Access is evil blah blah blah
Yup, we agree, but the realities of development are what they are. Seriously though this is the way it’s going to work.
We will be selling the JetStar at a discounted amount TBD whilst she is in Early Access and it will ONLY be available from our direct website.
We are planning weekly/fortnightly updates until she is finished.
There will be a MASSIVE notice on the sales page to NOT purchase if you do not want an IN DEVELOPMENT product and that we look forward to your purchase on release. 
There will be a 2020 and 2024 release and (as soon as we get access to the SDK like all the other devs) we’ll be adding as many native 2024 things to the '24 release as we can.
The 2020 release WILL be cheaper than the 2024 release. We are CONSIDERING an upgrade path but that is still to be determined considering we STILL don’t have access to the SDK!
The flight model and interior are quite mature now (Mach 0.8 @ 40K’ LETS GO!) and we are also coding a full CIVAS INS instrument for the aircraft. During EA it will launch as INOP with functions added through to release.
At release the INS will use GPS system calls under the hood, which will be more than enough to get an idea of how these things worked. BUT if we get enough interest from the community (read: sales) then we will code a complete INS calculation and it will NOT use ANY GPS calls."