diff --git a/.travis.yml b/.travis.yml
index f0d9a023..ef69836f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -66,7 +66,7 @@ jobs:
       stage: installation tests
       install: skip
       script: ./tests/docker/build
-      env: DISTRO=centos-latest PYVER=2
+      env: DISTRO=centos-latest PYVER=3
 
     # Ubuntu, latest
     - <<: *installation-stage
diff --git a/CHANGES.rst b/CHANGES.rst
index b5efd82f..c62cd635 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -3,6 +3,13 @@ Change log
 
 .. note:: **Upgrade notes**: after upgrading, run the ``arouteserver setup-templates`` command to sync the local templates with those distributed with the new version. More details on the `Upgrading <https://arouteserver.readthedocs.io/en/latest/INSTALLATION.html#upgrading>`__ section of the documentation.
 
+v0.22.2
+-------
+
+- Fix: prevent environment variables with unknown escapes (like `\u`) from interrupting the execution.
+
+  Related: `issue #50 on GitHub <https://github.com/pierky/arouteserver/issues/50>`_.
+
 v0.22.1
 -------
 
diff --git a/pierky/arouteserver/config/base.py b/pierky/arouteserver/config/base.py
index d9ff3157..440a4039 100644
--- a/pierky/arouteserver/config/base.py
+++ b/pierky/arouteserver/config/base.py
@@ -77,8 +77,7 @@ def expand_include(lines):
 
         def expand_env_vars(doc):
             res = doc
-            for v in os.environ:
-                res = re.sub("\$\{" + v + "\}", os.environ[v], res)
+            res = os.path.expandvars(res)
             res = re.sub("\$\{[A-Za-z0-9_]+\}", "", res)
             return res
 
diff --git a/pierky/arouteserver/version.py b/pierky/arouteserver/version.py
index 4e5b78be..be578d87 100644
--- a/pierky/arouteserver/version.py
+++ b/pierky/arouteserver/version.py
@@ -13,5 +13,5 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-__version__ = "0.22.1" # pragma: no cover
+__version__ = "0.22.2-alpha3" # pragma: no cover
 COPYRIGHT_YEAR = 2019 # pragma: no cover
diff --git a/tests/docker/centos-latest_py2.m4 b/tests/docker/centos-latest_py3.m4
similarity index 70%
rename from tests/docker/centos-latest_py2.m4
rename to tests/docker/centos-latest_py3.m4
index 7667a835..69808380 100644
--- a/tests/docker/centos-latest_py2.m4
+++ b/tests/docker/centos-latest_py3.m4
@@ -4,8 +4,11 @@ include(`base.m4')
 
 RUN yum -y update && yum -y install epel-release
 RUN yum -y update && yum -y install \
-	python-pip \
-	python-devel \
+	python3-pip \
+	python3-devel \
 	gcc
 
+ENV python=python3
+ENV pip=pip3
+
 include(`install.m4')
diff --git a/tests/static/test_cfg_general.py b/tests/static/test_cfg_general.py
index ac45422a..57d3a9f1 100644
--- a/tests/static/test_cfg_general.py
+++ b/tests/static/test_cfg_general.py
@@ -1411,3 +1411,20 @@ def test_env_vars_corrupted(self):
             "  router_id: ${ROUTER_ID\n"
         )
         self._contains_err("Invalid IPv4 address: ${ROUTER_ID")
+
+    @mock.patch.dict(os.environ, {"ROUTER_ID": "192.0.2.1", "BAD_ESCAPE": r"\u"})
+    def test_env_vars_bad_escape(self):
+        """{}: environment variables: ok (bad escape)"""
+
+        self.cfg._load_from_yaml(
+            "cfg:\n"
+            "  rs_as: 999\n"
+            "  router_id: ${ROUTER_ID}\n"
+            "  filtering:\n"
+            "    global_black_list_pref: ${GLOBAL_BLACK_LIST_PREF}\n"
+        )
+        self.cfg.parse()
+        self._contains_err()
+
+        self.assertEqual(self.cfg["router_id"], "192.0.2.1")
+        self.assertEqual(self.cfg["filtering"]["global_black_list_pref"], None)