diff --git a/configure.ac b/configure.ac
index 4cb3e27..79b0ce8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -110,14 +110,19 @@ dnl ############################################################################
 dnl # Release 1.6.4:
 dnl # "current:revision:age"
 dnl #
+dnl # - Code has changed in threadutil
+dnl #	revision: 1 -> 2
+dnl # - Code has changed in upnp
+dnl #	revision: 2 -> 3
+dnl #
 dnl #AC_SUBST([LT_VERSION_IXML],       [2:4:0])
-dnl #AC_SUBST([LT_VERSION_THREADUTIL], [4:1:2])
-dnl #AC_SUBST([LT_VERSION_UPNP],       [3:2:0])
+dnl #AC_SUBST([LT_VERSION_THREADUTIL], [4:2:2])
+dnl #AC_SUBST([LT_VERSION_UPNP],       [3:3:0])
 dnl #
 dnl ############################################################################
 AC_SUBST([LT_VERSION_IXML],       [2:4:0])
-AC_SUBST([LT_VERSION_THREADUTIL], [4:1:2])
-AC_SUBST([LT_VERSION_UPNP],       [3:2:0])
+AC_SUBST([LT_VERSION_THREADUTIL], [4:2:2])
+AC_SUBST([LT_VERSION_UPNP],       [3:3:0])
 dnl ############################################################################
 dnl # Repeating the algorithm to place it closer to the modificatin place:
 dnl # 	- library code modified:		revision++