diff --git a/Makefile b/Makefile
index cfe5aee..c5eb841 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@
 #
 TMPDIR     ?= /tmp
 DIST_PREFIX = ${TMPDIR}
-VERSION     = 4.9
+VERSION     = 4.9.1
 DEBVERSION  = $(shell echo $(VERSION)|sed 's/\(rc\|pre\|beta\|alpha\)/~\1/')
 BASE        = xen-tools
 VCS         = git
diff --git a/bin/xen-create-image b/bin/xen-create-image
index 943a832..8cbcf1a 100755
--- a/bin/xen-create-image
+++ b/bin/xen-create-image
@@ -872,7 +872,7 @@ my $MOUNT_POINT = undef;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 #
diff --git a/bin/xen-create-nfs b/bin/xen-create-nfs
index 37b9c2c..6c42633 100755
--- a/bin/xen-create-nfs
+++ b/bin/xen-create-nfs
@@ -121,7 +121,7 @@ $CONFIG{ 'template' } = '/etc/xen-tools/xm-nfs.tmpl';
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 # store version number away.
diff --git a/bin/xen-delete-image b/bin/xen-delete-image
index cdfb0a0..f86e674 100755
--- a/bin/xen-delete-image
+++ b/bin/xen-delete-image
@@ -167,7 +167,7 @@ my %CONFIG;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 #
diff --git a/bin/xen-list-images b/bin/xen-list-images
index 56b62ad..07dfddf 100755
--- a/bin/xen-list-images
+++ b/bin/xen-list-images
@@ -106,7 +106,7 @@ $CONFIG{ 'extension' } = '.cfg';
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 
diff --git a/bin/xen-resize-guest b/bin/xen-resize-guest
index 778913d..dd8053f 100755
--- a/bin/xen-resize-guest
+++ b/bin/xen-resize-guest
@@ -111,7 +111,7 @@ my %CONFIG;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 #
diff --git a/bin/xen-update-image b/bin/xen-update-image
index 1fd2f74..f4263cc 100755
--- a/bin/xen-update-image
+++ b/bin/xen-update-image
@@ -113,7 +113,7 @@ my %CONFIG;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 #
diff --git a/bin/xt-create-xen-config b/bin/xt-create-xen-config
index c6ba851..f05f6b8 100755
--- a/bin/xt-create-xen-config
+++ b/bin/xt-create-xen-config
@@ -148,7 +148,7 @@ $CONFIG{ 'extension' } = '.cfg';
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 
diff --git a/bin/xt-customize-image b/bin/xt-customize-image
index e101205..d889b2d 100755
--- a/bin/xt-customize-image
+++ b/bin/xt-customize-image
@@ -100,7 +100,7 @@ my %CONFIG;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 
diff --git a/bin/xt-guess-suite-and-mirror b/bin/xt-guess-suite-and-mirror
index 0991b89..315739f 100755
--- a/bin/xt-guess-suite-and-mirror
+++ b/bin/xt-guess-suite-and-mirror
@@ -79,7 +79,7 @@ use strict;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 # Init
 my $mirror = '';
diff --git a/bin/xt-install-image b/bin/xt-install-image
index f57c38e..c3568e1 100755
--- a/bin/xt-install-image
+++ b/bin/xt-install-image
@@ -113,7 +113,7 @@ my %CONFIG;
 #
 # Release number.
 #
-my $RELEASE = '4.9';
+my $RELEASE = '4.9.1';
 
 
 #
diff --git a/debian/changelog b/debian/changelog
index 393f747..1b92700 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+xen-tools (4.9.1-1) UNRELEASED; urgency=medium
+
+  * New upstream bugfix release.
+    + Fix missing "|" in regex in Debian's 20-setup-apt. (Closes: #997668)
+
+ -- Axel Beckert <abe@debian.org>  Sun, 24 Oct 2021 02:02:49 +0200
+
 xen-tools (4.9-1) unstable; urgency=medium
 
   * New upstream bugfix and minor feature release.
diff --git a/hooks/debian/20-setup-apt b/hooks/debian/20-setup-apt
index 1bcdec8..011dbcd 100755
--- a/hooks/debian/20-setup-apt
+++ b/hooks/debian/20-setup-apt
@@ -66,7 +66,7 @@ if ( test "${dist}" "!=" "sid" && test "${dist}" "!=" "unstable" && \
      test -e /etc/apt/sources.list && \
      grep ^deb.*security -r /etc/apt/sources.list /etc/apt/sources.list.d >/dev/null 2>/dev/null ) ; then
 
-    if echo "${dist}" | egrep -q '\b(sarge|etch|lenny|squeeze|wheezyjessie|stretch|buster)\b'; then
+    if echo "${dist}" | egrep -q '\b(sarge|etch|lenny|squeeze|wheezy|jessie|stretch|buster)\b'; then
 
         cat <<E_O_APT >> ${prefix}/etc/apt/sources.list
 #