diff --git a/README.rst b/README.rst
index cddb102a0..c899f0d8c 100644
--- a/README.rst
+++ b/README.rst
@@ -53,8 +53,8 @@ Other popular building blocks that are part of the OpenWISP ecosystem are:
   provides device status monitoring, collection of metrics, charts,
   alerts, possibility to define custom checks
 - `openwisp-firmware-upgrader
-  <https://openwisp.io/docs/stable/firmware-upgrader/>`_: automated firmware
-  upgrades (single devices or mass network upgrades)
+  <https://openwisp.io/docs/stable/firmware-upgrader/>`_: automated
+  firmware upgrades (single devices or mass network upgrades)
 - `openwisp-radius <https://openwisp.io/docs/stable/user/radius.html>`_:
   based on FreeRADIUS, allows to implement network access authentication
   systems like 802.1x WPA2 Enterprise, captive portal authentication,
@@ -65,10 +65,11 @@ Other popular building blocks that are part of the OpenWISP ecosystem are:
   daemons or other network software (e.g.: OpenVPN); it can be used in
   conjunction with openwisp-monitoring to get a better idea of the state
   of the network
-- `openwisp-ipam <https://openwisp.io/docs/stable/ipam/>`_: allows to manage
-  the assignment of IP addresses used in the network
-- `openwisp-notifications <https://openwisp.io/docs/stable/notifications/>`_:
-  allows users to be aware of important events happening in the network.
+- `openwisp-ipam <https://openwisp.io/docs/stable/ipam/>`_: allows to
+  manage the assignment of IP addresses used in the network
+- `openwisp-notifications
+  <https://openwisp.io/docs/stable/notifications/>`_: allows users to be
+  aware of important events happening in the network.
 
 **For a more complete overview of the OpenWISP modules and architecture**,
 see the `OpenWISP Architecture Overview
diff --git a/openwisp_controller/__init__.py b/openwisp_controller/__init__.py
index 6e2bfeb2a..d35f51f21 100644
--- a/openwisp_controller/__init__.py
+++ b/openwisp_controller/__init__.py
@@ -1,4 +1,4 @@
-VERSION = (1, 1, 0, 'final')
+VERSION = (1, 2, 0, 'alpha')
 __version__ = VERSION  # alias
 
 
diff --git a/openwisp_controller/config/base/template.py b/openwisp_controller/config/base/template.py
index 1ac764882..25c6a7d00 100644
--- a/openwisp_controller/config/base/template.py
+++ b/openwisp_controller/config/base/template.py
@@ -6,6 +6,7 @@
 from django.db import models, transaction
 from django.utils.translation import gettext_lazy as _
 from jsonfield import JSONField
+from netjsonconfig.exceptions import ValidationError as NetjsonconfigValidationError
 from swapper import get_model_name
 from taggit.managers import TaggableManager
 
@@ -115,7 +116,14 @@ def save(self, *args, **kwargs):
             if hasattr(self, 'backend_instance'):
                 del self.backend_instance
             current = self.__class__.objects.get(pk=self.pk)
-            update_related_config_status = self.checksum != current.checksum
+            try:
+                current_checksum = current.checksum
+            except NetjsonconfigValidationError:
+                # If the Netjsonconfig library upgrade changes the schema,
+                # the old configuration may become invalid, raising an exception.
+                # Setting the checksum to None forces related configurations to update.
+                current_checksum = None
+            update_related_config_status = self.checksum != current_checksum
         # save current changes
         super().save(*args, **kwargs)
         # update relations
diff --git a/openwisp_controller/config/tests/test_template.py b/openwisp_controller/config/tests/test_template.py
index 914499e7f..53540c6ea 100644
--- a/openwisp_controller/config/tests/test_template.py
+++ b/openwisp_controller/config/tests/test_template.py
@@ -7,6 +7,7 @@
 from django.db import transaction
 from django.test import TestCase, TransactionTestCase
 from netjsonconfig import OpenWrt
+from netjsonconfig.exceptions import ValidationError as NetjsonconfigValidationError
 from swapper import load_model
 
 from openwisp_utils.tests import catch_signal
@@ -500,6 +501,20 @@ def test_required_vpn_template_corner_case(self):
         # {'__all__': ['VPN client with this Config and Vpn already exists.']}
         self.assertIsNotNone(vpn_client)
 
+    def test_regression_preventing_from_fixing_invalid_conf(self):
+        template = self._create_template()
+        # create a template with an invalid configuration
+        Template.objects.update(config={'interfaces': [{'name': 'eth0', 'type': ''}]})
+        # ensure the configuration raises ValidationError
+        with self.assertRaises(NetjsonconfigValidationError):
+            template.refresh_from_db()
+            del template.backend_instance
+            template.checksum
+        del template.backend_instance
+        template.config = {'interfaces': [{'name': 'eth0', 'type': 'ethernet'}]}
+        template.full_clean()
+        template.save()
+
 
 class TestTemplateTransaction(
     TransactionTestMixin,