diff --git a/coriolis/osmorphing/debian.py b/coriolis/osmorphing/debian.py
index f135d2b1..6f87c1ef 100644
--- a/coriolis/osmorphing/debian.py
+++ b/coriolis/osmorphing/debian.py
@@ -158,7 +158,7 @@ def install_packages(self, package_names):
             apt_get_cmd = (
                 '/bin/bash -c "DEBIAN_FRONTEND=noninteractive '
                 'apt-get install %s -y '
-                '-o Dpkg::Option::=\'--force-confdef\'"' % (
+                '-o Dpkg::Options::=\'--force-confdef\'"' % (
                     " ".join(package_names)))
             self._exec_cmd_chroot(apt_get_cmd)
         except Exception as err:
diff --git a/coriolis/tests/osmorphing/test_debian.py b/coriolis/tests/osmorphing/test_debian.py
index fd1383f0..d4c9a0c4 100644
--- a/coriolis/tests/osmorphing/test_debian.py
+++ b/coriolis/tests/osmorphing/test_debian.py
@@ -243,7 +243,7 @@ def test_install_packages(self, mock_exec_cmd_chroot):
         apt_get_cmd = (
             '/bin/bash -c "DEBIAN_FRONTEND=noninteractive '
             'apt-get install %s -y '
-            '-o Dpkg::Option::=\'--force-confdef\'"' % (
+            '-o Dpkg::Options::=\'--force-confdef\'"' % (
                 " ".join(self.package_names)))
         deb_reconfigure_cmd = "dpkg --configure --force-confold -a"