Drug kingpin Demetrius "Big Meech" Flenory is out of prison, but he still has some boxes to check for total freedom ... including supervised release once he finishes out the remainder of his sentence in a halfway house, and restrictions on drug and alcohol use.

Big Meech, who co-founded the notorious Black Mafia Family, has a projected release date of January 27, 2026 ... according to the Federal Bureau of Prisons ... but he won't have the feds completely off his back until much later.

Instead, legal docs obtained by TMZ show Big Meech still has supervised release for 5 years with some special conditions ... namely, participating in a substance abuse program which may include drug and alcohol testing.

Big Meech was arrested way back in 2005, and in 2008 he was sentenced to 30 years in prison after being convicted on charges related to drug trafficking and money laundering.

Earlier this year, a judge shortened his sentence by almost 3 years ... and on Tuesday Big Meech was transferred from a federal prison in Florida to a halfway house, where he will serve out the remainder of his sentence before the supervised release kicks in.

LeBron James is among the celebs celebrating Big Meech's progress ... with the NBA superstar tweeting, "Welcome home Big Meech!!"