Let’s Encrypt allows subscribers to validate domain control using any one of a few different validation methods. For much of the time Let’s Encrypt has been operating, the options were “DNS-01”, “HTTP-01”, and “TLS-SNI-01”. We recently introduced the “TLS-ALPN-01” method. Today we are announcing that we will end all support for the TLS-SNI-01 validation method on February 13, 2019 [edit: February
![March 13, 2019: End-of-Life for All TLS-SNI-01 Validation Support](https://cdn-ak-scissors.b.st-hatena.com/image/square/11493d38279fd95c5c55cd262bc340aa693ee7ec/height=288;version=1;width=512/https%3A%2F%2Fglobal.discourse-cdn.com%2Fletsencrypt%2Foriginal%2F3X%2F4%2Fc%2F4c5760509a18adfc3bc657ba8bd49b301faaa66b.png)