diff --git a/README.md b/README.md
index 6b03d03..b846238 100644
--- a/README.md
+++ b/README.md
@@ -49,4 +49,4 @@ LICENSING info for 3.x is in the [COPYING.md](COPYING.md) file
 
 We are attempting to adhere to the POSIX standard, which can be found here:
 
-http://pubs.opengroup.org/onlinepubs/9699919799/
+https://pubs.opengroup.org/onlinepubs/9699919799/