diff --git a/configure.ac b/configure.ac
index e7cf8041..fb869708 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,8 +39,8 @@ AM_MAINTAINER_MODE
 
 dnl Versioning.
 dnl Don't fill the ALPHA_VERSION field, if not applicable.
-LIBTIFF_MAJOR_VERSION=3
-LIBTIFF_MINOR_VERSION=9
+LIBTIFF_MAJOR_VERSION=4
+LIBTIFF_MINOR_VERSION=3
 LIBTIFF_MICRO_VERSION=7
 LIBTIFF_ALPHA_VERSION=
 LIBTIFF_VERSION=$LIBTIFF_MAJOR_VERSION.$LIBTIFF_MINOR_VERSION.$LIBTIFF_MICRO_VERSION$LIBTIFF_ALPHA_VERSION