France coach Didier Deschamps has replaced Jeremy Mathieu with Valencia's Eliaquim Mangala despite insisting the Barcelona defender is "not finished."
Jagielka, 34, failed to make former Three Lions boss Roy Hodgson's selection for the summer's tournament in France.
Gundogan, 25, last played for Germany in a friendly against France on Nov. 13.
England's players received a motivational postcard from Sam Allardyce two days after he had left his job as national team manager.
Iniesta missed last month's international wins against Belgium and Liechtenstein with a knee injury but has since returned to fitness.
Wayne Rooney will remain as England captain under interim manager Gareth Southgate, according to multiple reports.