It was released on blu-ray.

HBO Max is USA only and has no ambition to launch overseas as yet as HBO has 10 year partnership rights in most countries.

Here are the 3 main English speaking nations and where to view the movie:

• Australia: HBO partner is Foxtel, HBO Max content will be on Streaming service "Binge" also owned by Foxtel (Confirmed).
• Canada: The Synder cut will be available on the streaming service "Crave" ( Confirmed).
• UK: As Sky has an HBO partnership agreement it is available through Sky Cinema.

Other contries:

• Asia: The Snyder Cut will be available on HBO Go (Confirmed).
• Brazil: HBOX Max is coming to Brazil, this is where you will be able to stream The Snyder Cut (Confirmed).
• France: The Snyder Cut will be available in France on April 22, 2021 (Confirmed). And the 18 March on Apple TV, iTunes, CanalVOD, Orange, Google Play, Youtube, Amazon Prime Video, Sony Play Station, Microsoft Xbox, Rakuten TV, Filmo TV, Universcine, Bbox VOD, Videofutur and SFR.
• Nordic contries: The Snyder Cut will be available on HBO Nordic on March 18, 2021 (Confirmed).
• Eastern Europe: HBO Go
• Portugal: HBO Portugal
• Russia: Kinopoisk

Justice League (2017) was initially shot in 2016 by Zack Snyder and by January 2017, Snyder had a 3 hour 34 min cut of the film. Zack Snyder left the project in May 2017 to deal with a family tragedy. Joss Whedon was his replacement to finish the film. Whedon as instructed by the studio then reshot up to 80% of the film, changed the score and edited it into a 2 hour runtime. This cut of the film famously had to CGI Henry Cavills' face due to the presence of a moustache he was contracted to keep whilst shooting Mission Impossible: Fallout.

Zack Snyder's Justice League (2021) is the uncompromised version of what was first shot in 2016 with 5 minutes of additional footage that was shot in 2020. It is 4 hours and 2 mins long and only contains what Snyder shot as well and uses Tom Holkenborgs' score.

Zack Snyder also decided to present his version in the 4:3 aspect ratio whereas the original version was presented in widescreen format.

Yes, that's true. Zack Snyder didn't get payment for working on the "Snyder Cut" from 2020 May to 2021 March (this allowed him to have complete control over the movie with 0 studio interference), though he did get paid the first time he worked on the project until 2017 March.

Justice League (2017) was initially shot in 2016 by Zack Snyder and by January 2017, Snyder had a 3 hour 34 min cut of the film. Zack Snyder left the project in May 2017 to deal with a family tragedy. Joss Whedon was his replacement to finish the film. Whedon as instructed by the studio then reshot up to 80% of the film, changed the score and edited it into a 2 hour runtime. This cut of the film famously had to CGI Henry Cavills' face due to the presence of a moustache he was contracted to keep whilst shooting Mission Impossible: Fallout.

Zack Snyder's Justice League (2021) is the uncompromised version of what was first shot in 2016 with 5 minutes of additional footage that was shot in 2020. It is 4 hours and 2 mins long and only contains what Snyder shot as well and uses Tom Holkenborgs' score. The 4 hour duration is made of six chapters, and it may as well be viewed as episodes of a web series, which was a format that the director had considered releasing previously.

No, it comes free with the subscription.

There's some violence and gore that pushes passed the limits of PG-13. Also there's more swearing.

Real Life answer: Different studios (TV vs movie). Different directors. Different visions. In Heather Ledger's case, he tragically died before he could reprise the role.

In-Universe answer: All of the live-action Jokers occupy a different universe within the DC Multiverse.

He does appear, but as Officer Jerry. He's the cheerful cop who Lois Lane gives a cup of coffee to at the Superman Memorial in Metropolis following his battle with Doomsday. Presumably his character of Ben Sadowsky was created for Joss Whedon's edited-down cut of Justice League.

No one has answered this question yet.

Now that the DC Extended Cinematic Universe is being cancelled in favor of the James Gunn-led DC Universe, it is more than likely that there will be a reboot of the Justice League movie that will have no connection to this movie.

The Parademons, as explained in universe in the Golden Age of Heroes flashback, are essentially brainless zombie-soldiers given horrific new bodies born from the dead and dying population of a planet that has been conquered using the Unity. Given that Steppenwolf has been conquering worlds in the name of Darkseid for quite some time, he has probably unleashed a Unity or two before and transformed entire populations to be Parademons.

As to how he transports them, Steppenwolf is prominently shown using a technology or ability of the New Gods (a race of which he is a member of) called a Boom Tube that is literally a portal that can bridge two points in space (much like the Tessaract/Space Stone in The Avengers or the Warp Drive in Event Horizon) and allow a person to travel between them. When he arrives on Themyscira to claim the Mother Box the Amazons guard, he also brings in some Parademons through the Boom Tube. Since Steppenwolf can create Boom Tubes with seemingly no effort (he is a New God, after all), it's reasonable to believe he can just teleport his troops to any place. Also, since he has conquered many world before, he has a good supply of replacements he can bring over from other conquered worlds to Earth to help him out.

The Terrorists that Diana fights in the early part of the movie have a pretty flawed logic. Even though blowing up the Old Bailey would have a very detrimental effect on the British Government, probably on the same level as 9/11 was to America, to the best of this poster's knowledge, blowing up four blocks and a major London courthouse would certainly not plunge all of Europe back into the Dark Ages. However, not all Terrorists are cold and calculating criminals, as it is clear that they didn't think the plan through.