diff --git a/branches/ucs-4.0/ucs-4.0-4/base/univention-updater/modules/univention/updater/mirror.py b/branches/ucs-4.0/ucs-4.0-4/base/univention-updater/modules/univention/updater/mirror.py
index 2d0da13..2c6c2a2 100644
--- a/branches/ucs-4.0/ucs-4.0-4/base/univention-updater/modules/univention/updater/mirror.py
+++ b/branches/ucs-4.0/ucs-4.0-4/base/univention-updater/modules/univention/updater/mirror.py
@@ -39,6 +39,7 @@ import itertools
 import logging
 from operator import itemgetter
 from debian.deb822 import Packages
+from apt import apt_pkg
 
 from tools import UniventionUpdater, UCS_Version, NullHandler
 try:
@@ -274,11 +275,26 @@ class UniventionMirror( UniventionUpdater ):
 
 	def _compress(self, filename):
 		self.log.debug('Compressing %s ...', filename)
-		subprocess.call(
+		sorter = subprocess.Popen(
+			('apt-sortpkgs', filename),
+			stdout=subprocess.PIPE,
+		)
+		compressor = subprocess.Popen(
 			('gzip',),
-			stdin=open(filename, 'rb'),
+			stdin=subprocess.PIPE,
 			stdout=open(filename + '.gz', 'wb'),
 		)
+		prev = None
+		for pkg in Packages.iter_paragraphs(sorter.stdout):
+			if prev:
+				if prev["Package"] != pkg["Package"]:
+					compressor.stdin.write("%s\n" % prev)
+				elif apt_pkg.version_compare(prev["Version"], pkg["Version"]) >= 0:
+					continue
+			prev = pkg
+		if prev:
+			compressor.stdin.write("%s\n" % prev)
+		compressor.stdin.close()
 
 	def _release(self, outdir, dist, archs, version):
 		rel_name = os.path.join(outdir, 'dists', dist, 'Release')
diff --git a/branches/ucs-4.1/ucs-4.1-1/base/univention-updater/modules/univention/updater/mirror.py b/branches/ucs-4.1/ucs-4.1-1/base/univention-updater/modules/univention/updater/mirror.py
index 9abf547..bdf5988 100644
--- a/branches/ucs-4.1/ucs-4.1-1/base/univention-updater/modules/univention/updater/mirror.py
+++ b/branches/ucs-4.1/ucs-4.1-1/base/univention-updater/modules/univention/updater/mirror.py
@@ -39,6 +39,7 @@ import itertools
 import logging
 from operator import itemgetter
 from debian.deb822 import Packages
+from apt import apt_pkg
 
 from tools import UniventionUpdater, NullHandler
 from ucs_version import UCS_Version
@@ -275,11 +276,26 @@ class UniventionMirror(UniventionUpdater):
 
     def _compress(self, filename):
         self.log.debug('Compressing %s ...', filename)
-        subprocess.call(
+        sorter = subprocess.Popen(
+            ('apt-sortpkgs', filename),
+            stdout=subprocess.PIPE,
+        )
+        compressor = subprocess.Popen(
             ('gzip',),
-            stdin=open(filename, 'rb'),
+            stdin=subprocess.PIPE,
             stdout=open(filename + '.gz', 'wb'),
         )
+        prev = None
+        for pkg in Packages.iter_paragraphs(sorter.stdout):
+            if prev:
+                if prev["Package"] != pkg["Package"]:
+                    compressor.stdin.write("%s\n" % prev)
+                elif apt_pkg.version_compare(prev["Version"], pkg["Version"]) >= 0:
+                    continue
+            prev = pkg
+        if prev:
+            compressor.stdin.write("%s\n" % prev)
+        compressor.stdin.close()
 
     def _release(self, outdir, dist, archs, version):
         rel_name = os.path.join(outdir, 'dists', dist, 'Release')