Salahdz 1 Posted October 3, 2021 hello every one i developped an application with delphi 10.4.2 that use ds proovider connexion to retreview data from a server buy when i opened my project on delphi 11 it won't compile, and the error is : "[DCC fatal Error ] TabbedFormwithNavigation.pas(15): F2051 the unit Data.SqlExpr was compiled with a diferent version System.SysUtils.FreeAndNil" and it point in Datasnap.DSConnect event if i create a new project and i put dsproviderconnection the same probleme is shown any one for help Thank you Share this post Link to post