Modern XMPP solved problem of loosing messages silently when a TCP connection is broken only with one of later added XEPs extensions while ancient SMTP did it f

Modern XMPP solved problem of loosing messages silently when a TCP connection is broken only with one of later added XEPs extensions while ancient SMTP did it from the beginning (a messages will be retried unless there was a response to dot command). Probably SMTP authors better understood how TCP works. Modern is not automatically implies that lessons of the past was learned.