Boba Fett returned to Star Wars in The Mandalorian season 2, but while viewers only got a tease of him, Disney and Lucasfilm have noticeably made a big change to Boba Fett's armor. Presumed dead in Return of the Jedi, Boba Fett's fate has been a mystery in the franchise for decades. Fans learned a bit more about his origins and backstory in George Lucas' Star Wars prequel trilogy as well as in the Clone Wars animated series, but his story arc after the original trilogy has been up for discussion.
Years after he fell into a sarlacc pit, Boba Fett re-emerged on Tatooine without his armor, which had been found by the Jawas and later sold to the Marshal of Mos Pelgo, Cobb Vanth. Of course, Cobb Vanth wasn't a true Mandalorian - though it's not like Boba and Jango Fett were Mandalorians either. He only wanted a suit strong enough to help him defeat the mining collective, and that's precisely what he got in Boba Fett's armor. However, in addition to the armor being damaged, an upgrade of sorts was made to it.
At some point between when Boba Fett fell into the sarlacc pit and when Cobb Vanth acquired the Mandalorian gear, Boba Fett's armor received an upgrade that has been teased for decades yet never actually seen in action: a missile targeting system attached to the helmet's antenna. While it was believed during the 1980s and 1990s that Boba Fett had a targeting system attached to his antenna (specifically, an external targeting rangefinder), it was never confirmed because it was never shown in action. But here, Cobb Vanth successfully operated it at least twice.
Boba Fett's armor having a targeting system that controls the jet pack's rocket is a new development, even if it was previously thought to serve a function similar to it. After all, the camera attached to Sabine Wren's helmet (who is a true Mandalorian in Star Wars Rebels), which looked like Boba Fett's and was placed in the same area, wasn't a targeting system at all - rather, it was a holo-imager, which she used to photograph areas and objects for her personal collection.
On top of the targeting system, one other thing that stood out about Boba Fett's armor in The Mandalorian season 2, episode 1 is the red lights display on the chest plate. For most of Boba Fett's scenes in the original Star Wars trilogy, those lights weren't on; however, they still were there. It can be noticed more easily in some scenes when he's on Bespin, but here, The Mandalorian makes full use of those lights. It's actually a surprise that they're still working after all these years and especially after how much the armor has been through.