diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index d4996cf..3b8aeec 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -903,7 +903,7 @@
  *       IPv6 omits the colons (01020304...0f)
  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
  * - 'I6c' for IPv6 addresses printed as specified by
- *       http://www.ietf.org/id/draft-kawamura-ipv6-text-representation-03.txt
+ *       http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-00
  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
  *       Options for %pU are:
@@ -1188,7 +1188,7 @@
  * %pI6 print an IPv6 address with colons
  * %pi6 print an IPv6 address without colons
  * %pI6c print an IPv6 address as specified by
- *   http://www.ietf.org/id/draft-kawamura-ipv6-text-representation-03.txt
+ *   http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-00
  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
  *   case.
  * %n is ignored