If you haven't listened to the Serial Podcast then go do that now and then come back to read this.
Adnan was convicted in 2000 of killing his high school girlfriend, Hae Min Lee.
The case gained international attention when, in 2014, it was featured on the podcast Serial.
According to CBC News back in 2016 a lower court vacated his conviction on the grounds that his attorney, Cristina Gutierrez, had not cross-examined a witness who was crucial to his case.
The Attorney General of Maryland appealed that decision, which resulted in the question of whether or not to throw out the conviction going before the Maryland Court of Special Appeals.
In a 2-1 ruling on Thursday, the three-judge appeals court panel agreed with Syed's current lawyer, Justin Brown, that his trial lawyer had provided him with ineffective council during the original trial.
His lawyer confirmed that they had won the appeal on Twitter.
WE WON THE APPEAL. #FreeAdnan— Justin Brown (@CJBrownLaw) March 29, 2018