(although the ongoing IDW comic Star Trek: The Last Starship, whose writers previously teased to io9 that it had connections to the events of Starfleet Academy, suggested that the Federation was on the verge of incorporating every known galactic civilization into the Federation at the time of the Burn, with the Gorn being the last intergalactic outliers)
Although Klingons had been mentioned multiple times across Discovery‘s later seasons, the show never explored much of what happened to the Klingons by the 32nd century.
It’s interesting that they brought up The Last Starship in one context, but didn’t carry that forward to the discussion of the Klingons. As I understand it (without having actually read it), according to the comic,
Spoilers for Star Trek: The Last Starship
The Klingons did join the Federation, but a sect known as “The Black Path” attacked Earth in the wake of the Burn. This directly led to Earth’s secession from the Federation, and presumably the Klingons’ as well.
It’s interesting that they brought up The Last Starship in one context, but didn’t carry that forward to the discussion of the Klingons. As I understand it (without having actually read it), according to the comic,
Spoilers for Star Trek: The Last Starship
The Klingons did join the Federation, but a sect known as “The Black Path” attacked Earth in the wake of the Burn. This directly led to Earth’s secession from the Federation, and presumably the Klingons’ as well.