diff --git a/actions/matrixsynapse b/actions/matrixsynapse
index 020173f0f..5dc5b1bb4 100755
--- a/actions/matrixsynapse
+++ b/actions/matrixsynapse
@@ -5,12 +5,14 @@ Configuration helper for Matrix-Synapse server.
 """
 
 import argparse
+import pathlib
 
 import yaml
 
 from plinth import action_utils
-from plinth.modules.matrixsynapse import ORIG_CONF_PATH, STATIC_CONF_PATH, \
-    LISTENERS_CONF_PATH, REGISTRATION_CONF_PATH
+from plinth.modules.matrixsynapse import (LISTENERS_CONF_PATH, ORIG_CONF_PATH,
+                                          REGISTRATION_CONF_PATH,
+                                          STATIC_CONF_PATH)
 
 STATIC_CONFIG = {
     'max_upload_size':
@@ -47,6 +49,10 @@ def parse_arguments():
         '--domain-name',
         help='The domain name that will be used by Matrix Synapse')
 
+    subparsers.add_parser(
+        'move-old-conf',
+        help='Move old configuration file to backup before reinstall')
+
     subparsers.required = True
     return parser.parse_args()
 
@@ -110,6 +116,14 @@ def subcommand_public_registration(argument):
         action_utils.service_restart('matrix-synapse')
 
 
+def subcommand_move_old_conf(_arguments):
+    """Move old configuration to backup so it can be restored by reinstall."""
+    conf_file = pathlib.Path(ORIG_CONF_PATH)
+    if conf_file.exists():
+        backup_file = conf_file.with_suffix(conf_file.suffix + '.fbx-bak')
+        conf_file.replace(backup_file)
+
+
 def main():
     arguments = parse_arguments()
     sub_command = arguments.subcommand.replace('-', '_')
diff --git a/plinth/modules/matrixsynapse/__init__.py b/plinth/modules/matrixsynapse/__init__.py
index 19cd93257..97cf017a1 100644
--- a/plinth/modules/matrixsynapse/__init__.py
+++ b/plinth/modules/matrixsynapse/__init__.py
@@ -18,11 +18,10 @@ from plinth.daemon import Daemon
 from plinth.modules.apache.components import Webserver
 from plinth.modules.firewall.components import Firewall
 from plinth.modules.letsencrypt.components import LetsEncrypt
-from plinth.utils import Version
 
 from .manifest import backup, clients  # noqa, pylint: disable=unused-import
 
-version = 5
+version = 6
 
 managed_services = ['matrix-synapse']
 
@@ -111,31 +110,29 @@ class MatrixSynapseApp(app_module.App):
 def setup(helper, old_version=None):
     """Install and configure the module."""
     helper.install(managed_packages)
-    helper.call('post', actions.superuser_run, 'matrixsynapse',
-                ['post-install'])
-    helper.call('post', app.enable)
+    if old_version and old_version < 6:
+        helper.call('post', upgrade, helper)
+    else:
+        helper.call('post', actions.superuser_run, 'matrixsynapse',
+                    ['post-install'])
+
+    if not old_version:
+        helper.call('post', app.enable)
+
     app.get_component('letsencrypt-matrixsynapse').setup_certificates()
 
 
-def force_upgrade(helper, packages):
-    """Force upgrade matrix-synapse to resolve conffile prompt."""
-    if 'matrix-synapse' not in packages:
-        return False
-
-    # Allow any lower version to upgrade to 1.15.*
-    package = packages['matrix-synapse']
-    if Version(package['new_version']) > Version('1.16~'):
-        return False
-
+def upgrade(helper):
+    """Upgrade matrix-synapse configuration to avoid conffile prompt."""
     public_registration_status = get_public_registration_status()
-    helper.install(['matrix-synapse'], force_configuration='new')
+    actions.superuser_run('matrixsynapse', ['move-old-conf'])
+    helper.install(['matrix-synapse'], force_configuration='new',
+                   reinstall=True, force_missing_configuration=True)
     actions.superuser_run('matrixsynapse', ['post-install'])
     if public_registration_status:
         actions.superuser_run('matrixsynapse',
                               ['public-registration', 'enable'])
 
-    return True
-
 
 def setup_domain(domain_name):
     """Configure a domain name for matrixsynapse."""