SSL error 1409442E downloading file over HTTPS with TIdHTTP

Question

I'm using Delphi 10.3.3. The code below used to work but now I'm getting an error when trying to download a file over HTTPS:

Error connecting with SSL error:1409442E:SSL routines:SSL3_READ_BYTES:tlsv1 alert protocol version'

var
  ms : tmemorystream;
  ssl : TIdSSLIOHandlerSocketOpenSSL;
  source,dest : string;
begin
  source := 'https://www.myaddress.com/myfile.zip';
  dest := 'c:\myfile.zip';
  ms := TMemoryStream.Create;
  try
    if pos('https',source) > 0 then
    begin
      ssl := TIdSSLIOHandlerSocketOpenSSL.Create();
      idh.IOHandler := ssl;
    end;
    idhttp1.get(source,ms);
    ms.savetofile(dest);
    result := 'ok';
  finally
    ms.Free;
  end;
end;

Answer 1

TIdSSLIOHandlerSocketOpenSSL uses only TLS v1.0 by default and the server is rejecting that. You must explicitly allow newer TLS versions:

ssl := TIdSSLIOHandlerSocketOpenSSL.Create();
ssl.SSLOptions.SSLVersions := [sslvTLSv1, sslvTLSv1_1, sslvTLSv1_2];
idh.IOHandler := ssl;