How Does MTA-STS Improve Your Email Security?

Simple Mail Transfer Protocol or SMTP has easily exploitable security loopholes. Email routing protocols were designed in a time when cryptographic technology was at a nascent stage (e.g., the de-facto protocol for email transfer, SMTP, is nearly 40 years old now), and therefore security was not an important consideration. 
As a result, in most email systems encryption is still opportunistic,

Source:: The Hackers News