Conte spent two seasons in charge of the Premier League club, leading them to the title in his first year.
In any event, the working relationship between Conte and Chelsea is over - as soon as that is made public by the club, the appointment of Sarri, with Blues legend Gianfranco Zola as part of the backroom team, will nearly certainly follow shortly after.
The club's 64-word announcement was eventually made on Friday, ending with: "We wish Antonio every success in his future career".
Conte's future with the Roman Abramovich-owned club has looked uncertain for months, however, with the West Londoners failing to qualify for the coming season's Champions League after finishing fifth last season.
Conte was relieved of his duties after he conducted training at Cobham for the final time on Thursday morning before saying his goodbyes to players and staff.
"Thank you boss", Terry wrote on Twitter.
Wimbledon 2018 -- Juan Martin del Potro reaches quarterfinals
Spain's Nadal and Serbia's Djokovic have won 29 Grand Slam titles between them, including five previous victories at SW19. Argentina's Juan Martin Del Potro celebrates winning his the fourth round match against France's Gilles Simon .
Conte regularly questioned the club's ambition and dealings in the transfer window and departs after failing to guide the Blues into next season's Champions League.
The exuberant, passionate and, at times, bonkers Italian was popular among many Chelsea fans and there was lots of support for him after his tenure finally came to an end.
When Carlo Ancelotti was offloaded after two years in May 2011, despite winning the league and cup double in his maiden campaign, Chelsea recognised his "contribution and achievements" and welcomed him back to the club with open arms.
Napoli are also expecting compensation of around £4.5 million for Sarri, who is under contract even though he is no longer their coach.
He's heading to Chelsea along with his former manager at Napoli, Maurizio Sarri.