diff --git a/tools/release.sh b/tools/release.sh
index 12dfdb6ab..abd721a17 100755
--- a/tools/release.sh
+++ b/tools/release.sh
@@ -125,8 +125,8 @@ do_clean_all() {
 
 do_version_commit() {
 	[ "$*" ] || die "usage: $0 commit <message>"
-	git add configure.in || die "error: no version changes to commit"
-	git commit -q -m "$*" configure.in
+	git add configure.ac || die "error: no version changes to commit"
+	git commit -q -m "$*" configure.ac
 }
 
 do_version_finalize() {
@@ -281,7 +281,7 @@ do_reset() {
 	maybe_bootstrap
 	maybe_configure
 	do_clean_all
-	git checkout configure.in
+	git checkout configure.ac
 }
 
 LONGOPTS="fast,final,start-rc,next-tag:,next:,help"
diff --git a/tools/release/helpers.sh b/tools/release/helpers.sh
index 2dd5bae15..47d5782ab 100644
--- a/tools/release/helpers.sh
+++ b/tools/release/helpers.sh
@@ -6,15 +6,15 @@ die() {
 }
 
 package_info_load_name() {
-	grep AC_INIT configure.in | perl -ne 's/^.+\(\[([-\w]*)\],.+$/$1/ and print'
+	grep AC_INIT configure.ac | perl -ne 's/^.+\(\[([-\w]*)\],.+$/$1/ and print'
 }
 package_info_load_version() {
-	grep AC_INIT configure.in | perl -ne 's/^.+\[([-\w\.]*)\],$/$1/ and print'
+	grep AC_INIT configure.ac | perl -ne 's/^.+\[([-\w\.]*)\],$/$1/ and print'
 }
 
 package_info_load() {
-	[ -f "configure.in" ] || \
-		die "package_info_load: configure.in is missing"
+	[ -f "configure.ac" ] || \
+		die "package_info_load: configure.ac is missing"
 
 	PACKAGE_NAME="$(package_info_load_name)"
 	# todo: fix this
diff --git a/tools/release/version.sh b/tools/release/version.sh
index 8c6da2734..d6c9434b3 100755
--- a/tools/release/version.sh
+++ b/tools/release/version.sh
@@ -8,7 +8,7 @@
 # NOTE Use with care!  "RC" should only follow x.x.x, with
 # vendor tags after that.  Be traditional; avoid "rc0".
 
-# NOTE:  This *ONLY* updates the "configure.in" version tag.
+# NOTE:  This *ONLY* updates the "configure.ac" version tag.
 # It does not affect GIT tags.  Use this script immediately
 # before making a release, to remove the "-dev" tag and to
 # update the version label.  Then commit the change and tag
@@ -34,7 +34,7 @@ do_version_sed() {
 	local NEW_VERSION="$1"
 	local MSG="$2"
 
-	sed -i -e "/AC_INIT/ s|${OLD_VERSION}|${NEW_VERSION}|" configure.in
+	sed -i -e "/AC_INIT/ s|${OLD_VERSION}|${NEW_VERSION}|" configure.ac
 	package_info_load
 	echo "${MSG}: ${OLD_VERSION} -> ${NEW_VERSION}"
 }