Neither players deals will be extended.
The Club can also confirm that it will not seek to extend Jefferson Montero's loan from Swansea City.
Montero's loan is due to run out on 30 June.
The winger is in the last year of his contract at Swansea.
Goalkeeper Stockdale became Harry Redknapp's first signing for Blues in the summer of 2017, from Brighton & Hove Albion.
Stockdale made 39 appearances in his debut campaign before falling out of favour under Garry Monk.
In 2018/19 he had three Emergency Loan spells: at Southend United, Wycombe Wanderers and Coventry City.
This season the 34-year-old has made one appearance for Blues, in the Carabao Cup tie at Portsmouth in August, and was deputy to Lee Camp for the first three months.
Connal Trueman got an opportunity when Camp came out of the side in November and Stockdale rejoined Wycombe on loan in January.
His loan there expired on 4 May but will be extended to cover the remainder of the League One season, should it continue.
Left-back Keita, 24, came to Blues in the 2017 January transfer window, for an undisclosed fee from Italian side Virtus Entella.
He made 10 appearances in the remainder of that season, when Blues survived on the final day.
He came on as a substitute in the opening match of the next campaign but then suffered an injury and couldn't find a way back in as Jonathan Grounds was preferred and Cohen Bramhall signed on loan.
Keita subsequently went on loan to Bologna but made only three appearances.
In 2018/19 it was off to Belgium and a loan to Eupen before Keita returned to Blues.
He has made the matchday squad on a handful of occasions this season and been an unused substitute twice in February but has not added to his Blues appearance tally.
Montero, 30, joined Blues on a season's loan from Swansea on transfer deadline day in August.
He appeared in 19 games, of which 14 were as a substitute. Montero came back from a thigh injury suffered in August during his first start for the Club that kept him out for two months.
Blues would like to place on record our thanks to David, Cheick and Jefferson for their efforts and we wish them every success in the future.