Marvel fans are eagerly waiting for any "Iron Man 4" updates and its release date.

While avid fans have a lot of MCU movies to look forward to in the coming years, many are still wondering if Robert Downey Jr. will still don the famous Iron Man suit for another solo movie.  Sources are certain that RDJ will still be seen in the upcoming "Avengers" flicks, but a fourth solo movie is still up in the air.

Rumors are starting to circulate that "Iron Man 4" could be underway, but it will not involve Downey Jr. anymore.  Who will replace him to play the iconic Tony Stark?

"By that time [2020] Robert Downey Jr. would be 55 years old, which could make it more difficult for the actor to continue playing an action-heavy role such as that of Tony Stark aka Iron Man," Christian Today stated. "If the movie were to happen, it is possible the role of Tony Stark could be re-cast."

"Downey Jr. is also the most expensive actor on Marvel's payroll and as his involvement continues, it is possible that Disney and Marvel may refuse to take him for another movie if his fee is too high, even with the knowledge that the 'Iron Man' films have generated billions of dollars for the studios."

Meanwhile, all eyes are on the rumored feud that will transpire should "Iron Man 4" have a 2020 release date.  Sources claimed that the Marvel superhero could go head-to-head against DC's "Batman," as another adaptation of the Gotham hero is slated on the same date.

"With the upcoming release of 'Batman vs. Superman: Dawn of Justice' this coming March 25, the complexion of the superhero movie genre would certainly change and while no one would like to admit or dare say it at this time, the DC Extended Universe is expected to give the Marvel Cinematic Universe an excellent run for the money," Master Herald reported.

"By the time 2020 comes, it is most likely that the annual dose of Iron Man may have already worn thin the character among fans and a new offering like a refreshed Batman would be most welcome."

Stay tuned for more "Iron Man 4" MCU updates here!