The game has been available on PC since September 2018 (early access) and May 2019 (release 1.0). That's where we get our information.
I don't know how long this has been working underwrap
They've been working on the console version for more than 1 year. Just lately they reached the certainty of when it can be released. (Source: translation of Italian motorsportsrepublic podcast).
Can you please let us know how this two gen compatibility works?
That's a bit unclear (for PS5) at the moment if I understand correctly. Digital Foundry has a new video on the matter:
EDIT: I thought I would just post the whole interview translation here, as it contains some interesting info. All credit for translation goes to user Guidofoc on the ACC forums. I'm pasting his post unedited here:
------------------------------------------------------------
"OK. If I am not mistaken, the interview is a bit old, as Marco says that "there will be a SRO esports race in Monza" (that race has already taken place on March 29, right?), so I would say this is from 10+ days ago.
Some chat about how sim racing has a chance to emerge in this moment, also about the chances for a sim driver to become a real driver. A bit of critique to F1 for the disappointing esports event they did after the cancellation of the first GP.
Finally, at about 13:00 they start talking about ACC. Pleasure for the increasing success of the game and the DLC.
Question on the laser scan: are the tracks all done by you? Yes, all done by us. The Laguna Seca track for AC was the only one made "outside", by the guys who made the Luccaring mod for AC.
Concering the Unreal engine, Marco said they have received some help from Epic itself when they were developing the triple screen features.
Console version: they've been working on it for more than 1 year, just lately they reached the certainty of when it can be released.
They also announced a roadmap for PC:
GT4 was probably a surprise for the fans. Beautiful cars, less extreme, fun to drive. They joked they should do ACC GT4 as a standalone game. The unexpected thing that happened during the development was that the teams themselves went to them, they received a big number of emails from GT4 teams and drivers, and they want to cooperate because they need a sim to do training so the sooner they get a GT4 sim the better. They are asking for beta version so they can start testing and using it.
He also says that Amazon is a title sponsor so there could be news related to this (?).
Other chitchat on driving real race cars compared to simulated ones (Marco drove a Lamborghini Super Trofeo at Vallelunga). Marco argues that today's quick sim racers are perfectly able to drive real race cars (of course with the aid of some physical training).
When does the GT4 pack come out? End of June to mid-July (he mentioned Camaro, Aston Vantage, Ginetta). He says that there may be delays due to the Coronavirus because they are waiting for some data from some manufacturers.
Then the British pack, they are working on it and it should be ready by the end of the year.
The 1.4 build will come out in the next few weeks.
Question: have you thought about creating an advanced user guide for ACC? Yes, we have thought about it and it is not easy to create a good driving/setup guide, also because the localization needs lots of attention. At the same time, ACC allows rookie drivers to just jump into a car and race without any setup. When the player decides to put more time into ACC, he will discover the "depth" of the sim. In comparison, Marco said that he is playing a flight sim where even to take off you need to study a lot (steep learning curve)."
-----------------------------------------