'Iron Man 4' is a planned action-adventure and science-fiction film intended as the follow-up to Shane Black's 2013 release of the same name. Speculations emerged that the it may be scrapped due to Robert Downey Jr.'s increasing age and end of contract with Marvel. Meanwhile, Downey Jr. and Chris Evans engage in a satirical Twitter war over Ryan Reynold's 'Deapool'.

According to MNR Daily, the fourth installment to the highly popular 'Iron Man' standalone films in the Marvel Cinematic Universe (MCU) may not make it on the big screens any time soon. The film is not included in the list of Marvel's upcoming releases in the next few years.

It was speculated that should the film push through sometime in the year 2020 as part of future phases in the MCU, leading actor Robert Downey Jr. may be too old to play the titular Tony Stark a.k.a. Iron Man.

Downey Jr.'s contract with Marvel may also have ended by then. According to Morning News USA, the actor admitted, "I also recognize that I'll be turning 50 by the time I promote this movie. The clock is ticking down on the amount of memories and participation that I would allow myself and not embarrass the medium with." It was not confirmed whether Downey Jr. would be extending his contract with the studio.

Some rumors suggested that Ty Simpkins' Harley Keener may become the new protagonist for 'Iron Man 4'. The young character first appeared on 'Iron Man 3', where he formed an alliance with Iron Man. Simpkins also appeared on several feature films including 'Insidious', 'Revolutionary Road' and 'Jurassic World'.

Meanwhile, Downey Jr. is set to reprise his role in the upcoming 'Captain America: Civil War' scheduled to be released on May 6, 2016. He jokingly traded barbs with co-actor Chris Evans, who plays Steve Rogers a.k.a. Captain America in the MCU, after the latter praised Ryan Reynolds in the standalone 'Deadpool' film.

According to Entertainment Weekly, Evans took to Twitter to commend Reynolds for his performance as the titular character in 'Deadpool'. Reynolds responded that he was on Captain America's side for the imminent showdown between Cap and Iron Man in 'Civil War'.

Downey Jr. joined in by saying, "Et tu, D-pool? Gimme a shout when Rogers boots you out for "cussing"!". Evans jokingly replied that he was into swearing despite his alter ego.

Evans and Downey Jr. will meet head on in the new 'Civil War' film as allies-turned-enemies. The film is also set to introduce Chadwick Boseman's Black Panther as well as Tom Holland's Spider-Man.

'Iron Man 4' is a planned action-adventure and science-fiction film intended as a sequel to Shane Black's 'Iron Man 3' released in 2013. It is part of the MCU and is based on the Marvel comic book character of the same name.