MK Dons have signed defender Zak Jules from Walsall for an undisclosed fee and Sunderland striker Will Grigg on loan until the end of the season.
Grigg, 29, joined the Black Cats from Wigan for £4m in January 2019.
However, the Northern Ireland international, who spent 2014-15 on loan at MK, has scored just five goals in 47 league appearances for them.
Meanwhile, Sunderland have released striker Danny Graham, 35.
Graham re-joined the Stadium of Light side from Blackburn in September 2020 but failed to score in 14 league appearances.
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