diff --git a/debian/changelog b/debian/changelog
index 3a66c0f..a66b5f5 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,11 +1,15 @@
-nut (2.6.4-1) UNRELEASED; urgency=low
+nut (2.6.4-1) unstable; urgency=high
 
   * New upstream release (Closes: #671444)
   * acknowledges NMU (Closes: #613643)
   * debian/nut-client.init: fix action "start" and use of log_*_*msg
     LSB log functions (Closes: #675619)
+  * debian/nut-server.preinst: remove obsolete file(s) left in
+    /etc/udev/rules.d and related processing: udev files are now located
+    in /lib/udev/rules, and there is no reason to modify the dedicated
+    USB UPS rules (52-nut-usbups.rules) (Closes: #660072)
 
- -- Arnaud Quette <aquette@debian.org>  Fri, 01 Jun 2012 16:15:20 +0200
+ -- Arnaud Quette <aquette@debian.org>  Wed, 06 Jun 2012 21:03:50 +0200
 
 nut (2.6.3-2) unstable; urgency=low
 
diff --git a/debian/nut-server.preinst b/debian/nut-server.preinst
index 9999abe..587c150 100644
--- a/debian/nut-server.preinst
+++ b/debian/nut-server.preinst
@@ -1,19 +1,10 @@
 #!/bin/sh -e
 
 if [ "$1" = upgrade ]; then
-    # remove the obsolete udev file
-    [ -f /etc/udev/rules.d/025_nut-usbups.rules ] && rm -f /etc/udev/rules.d/025_nut-usbups.rules
-
-    # Remove previous rules if unchanged, otherwise move to new filename.
-    if [ -e "/etc/udev/rules.d/52_nut-usbups.rules" ]; then
-	    if [ "`md5sum \"/etc/udev/rules.d/52_nut-usbups.rules\" | sed -e \"s/ .*//\"`" = \
-		 "`dpkg-query -W -f='${Conffiles}' nut | sed -n -e \"\\\\' /etc/udev/rules.d/52_nut-usbups.rules's/.* //p\"`" ]
-	    then
-		    rm -f "/etc/udev/rules.d/52_nut-usbups.rules"
-	    else
-		    mv "/etc/udev/rules.d/52_nut-usbups.rules" "/etc/udev/rules.d/52-nut-usbups.rules"
-	    fi
-    fi
+	# remove the obsolete udev file(s)
+	[ -f /etc/udev/rules.d/025_nut-usbups.rules ] && rm -f /etc/udev/rules.d/025_nut-usbups.rules
+	[ -f /etc/udev/rules.d/52_nut-usbups.rules ] && rm -f /etc/udev/rules.d/52_nut-usbups.rules
+	[ -f /etc/udev/rules.d/52-nut-usbups.rules ] && rm -f /etc/udev/rules.d/52-nut-usbups.rules
 
 	# migrate /etc/default/nut to /etc/nut/nut.conf (part #1)
 	# we need to do this before default gets trashed