Today on August 26th, Sentai has announced via tweet and in their #sentaiathome-stream, virtual screenings of Made in Abyss Movie 3: Dawn of the Deep Soul will begin starting 18th September.[1]
Which platforms, if it will be region locked etc. have yet to be announced.
Furthermore, the stream featured interviews with the japanese voice actors of Riko, Reg and Nanachi.[2]
On September 4th, Sentai announced via tweet that the virtual screenings will only be aviable in the United States of America, Canada, United States Minor Outlying Islands, United Kingdom of Great Britain and Northern Ireland and South Africa. [3]
Tickets can be pre-ordered on this site for 19,99 dollars.
Futhermore, only two of the four Marulk OVAs will be included to be watchable after the movie per ticket.
Which one will apparently be random.[4]
Personal thoughts: I personally think it is horrible that Sentai region locked it to the point that Europeans will need a VPN to watch the movie while they could have easily obtained liecensing for the entire european room as well. The "tickets" are overprized and that one does not get all 4 Marulk OVAs with one ticket is bad distributation.