I think the red suit will evolve further. Iron Man, Cap, Thor, War Machine, Falcon (in Civil War), Deathlok, Loki, Hawkeye, Black Widow - every one of them has had a modified suit in the MCU. I don't see why DD would be different - by The Defenders I am sure the suit will have some changes to it.
three and a half years ago
Hey guys about the costume - every single Marvel hero has had costume upgrades in the time they've been on screen in the MCU. Why assume DD would be any different. He had *a* red suit at the end of this show - there is zero reason to think that will be the same red suit he wears in The Defenders.