The Owls' longest-serving player is now tied to the Hillsborough side until 2019.
Mignolet featured in Liverpool's win over Tottenham in the EFL Cup, but has recently been dropped in favour of Loris Karius.
West Ham United beat Chelsea in the last sixteen of the EFL Cup on Wednesday.
The midfielder put in a good performance for Arsenal this week as Spurs lost to Liverpool.
Celtic thrashed Ross County 4-0 last night, and Brendan Rodgers paid tribute to the 30-year-old.
Elliot has been sidelined since March because of a knee injury he suffered while on international duty.
The Championship club are currently searching for a new manager after the departure of Gary Caldwell.
The Australian international is set for Premier League interest in the winter from Crystal Palace, West Bromwich Albion and Middlesbrough.
Manchester City were dumped out of the EFL Cup after a 1-0 defeat by rivals Manchester United this week.
The winger was linked with a move to Everton in the summer and is out of contract next summer.
Dele Alli has accepted that he must develop a more ruthless edge in front of goal if he is to take his game to the next level. The Tottenham Hotspur midfielder has come a long way since the beginning of last season, establishing himself as a key player at club level and also with England.
It was not difficult to detect the prickliness in Kevin De Bruyne. Was Lionel Messi from another planet, the Manchester City forward was asked. “No, otherwise he wouldn’t be here,” De Bruyne shot back.
Ronald Koeman has said Ross Barkley’s omission against Manchester City should serve as a wake-up call to the Everton midfielder about the need for more aggression and end product in his game.