A small Delphi example is about SysUtils.FileAge. It has two overloads, of which one is deprecated. So the first call will give you a compiler warning.

DeprecatedFileAge.pas

program DeprecatedFileAge;

uses
  SysUtils;

{$APPTYPE CONSOLE}

var
  ExeName: string;
  IntegerAge: Integer;
  DateTimeAge: TDateTime;
begin
  ExeName := ParamStr(0);

  if FileExists(ExeName) then // [Pascal Warning] DeprecatedFileAge.dpr(17): W1000 Symbol 'FileAge' is deprecated
  begin
    IntegerAge := FileAge(ExeName);
    DateTimeAge := FileDateToDateTime(IntegerAge);
    Writeln(Format('Age of "%s" is "%s"', [ExeName, DateTimeToStr(DateTimeAge)]));
  end;

  if FileAge(ExeName, DateTimeAge) then
  begin
    Writeln(Format('Age of "%s" is "%s"', [ExeName, DateTimeToStr(DateTimeAge)]));
  end;
(*
  In de SysUtils unit:

{ FileAge returns the date-and-time stamp of the specified file. The return
  value can be converted to a TDateTime value using the FileDateToDateTime
  function. The return value is -1 if the file does not exist. This version
  does not support date-and-time stamps prior to 1980 and after 2107. }

function FileAge(const FileName: string): Integer; overload; deprecated;

{ FileAge retrieves the date-and-time stamp of the specified file as a
  TDateTime. This version supports all valid NTFS date-and-time stamps
  and returns a boolean value that indicates whether the specified
  file exists. }

{$IFDEF MSWINDOWS}
function FileAge(const FileName: string; out FileDateTime: TDateTime): Boolean; overload;
{$ENDIF}
*)
end.