The younger brother of the Manchester Arena bomber has formally entered not guilty pleas to multiple charges of murder.
At an Old Bailey hearing, Hashem Abedi's trial which was due to start next month was also delayed until the New Year.
On May 22 2017, Salman Abedi, 22, detonated a suicide vest as music fans left an Ariana Grande concert, killing 22 people and injuring 260 more.
His sibling, Hashem Abedi, who was raised in Manchester, travelled to Libya before the attack.
The defendant, now aged 22, was arrested in Tripoli and was extradited to the UK in July.
He appeared at the Old Bailey before senior judge Mr Justice Baker for a plea hearing on Tuesday.
The softly spoken defendant wore spectacles, a grey sweatshirt and burgundy T-shirt in the dock of court two.
It took six minutes for all the charges to be read out in court and for Abedi to enter not guilty pleas to each one in turn.
Abedi denied 22 counts of murder - one for each of the attack's victims.
They were: off-duty police officer Elaine McIver, 43, Saffie Roussos, 8, Sorrell Leczkowski, 14, Eilidh MacLeod, 14, Nell Jones, 14, Olivia Campbell-Hardy, 15, Megan Hurley, 15, Georgina Callander, 18, Chloe Rutherford,17, Liam Curry, 19, Courtney Boyle, 19, Philip Tron, 32, John Atkinson, 26, Martyn Hett, 29, Kelly Brewster, 32, Angelika Klis, 39, Marcin Klis, 42, Michelle Kiss, 45, Alison Howe, 45, Lisa Lees, 43, Wendy Fawell, 50 and Jane Tweddle, 51.
Abedi also faces a single count of attempted murder for all the other victims and conspiring with his brother to cause explosions.
During the hearing, the judge put off the trial from November 11 to January 13.
The case is expected to go on for up to eight weeks.
The defendant allegedly made successful and unsuccessful attempts to buy bomb-making chemicals.
It is claimed he helped in buying a Nissan Micra to store device components and he made detonator tubes for use in the explosive.
The defendant was remanded into custody at top security HMP Belmarsh.