Please read about how the system determines the year of a film, based on the release date types, here.

The one-off 2017 live gala performance is a materially different version of the project and should not be considered the 'release' - it was a musical stage show with live musical performances, lighting and visual effects, breaks added into the projection, etc. It's highly related, but it's simply not the same thing.

@Gorgonaut You can read the official festival event presentation here. Your description does not quite match the official one. But it's also possible that you have a better source describing the event. If so, please share. I would be interested to find a source talking about breaks in projection, as that would possibly make it a different project (meaning this entry would change into one for the 2020 finished version).

(Edit: Official presentation makes it seem like a movie screening with live music etc.)

I put a few quotes in the discussion section, but the specific description of breaks in the film comes from here, a review of the 2017 performance:

https://confidentials.com/manchester/mif-2017-last-and-first-men-reviewed-manchester-international-festival

"A discordant percussion section is accompanied by some effective lighting techniques, and beams reflected off mirrors and through the smoky air add to the haunting feeling. At times, the film stops and the lighting rig takes over as punctuation."

And it's not simply a live performance of the score as written, but a modified and improvised version - "Jóhannsson formed part of the orchestra by adding organ and subtle live electronics throughout. His electronic manipulation of the enchanting live soprano voices helped create a unique and uneasy air of extra-terrestrial discord."

Thanks. I agree that with that information this was not a movie screening, but more of an art event. I removed the 2017 release date. Closing topic.