diff --git a/docs/production/upgrade-or-modify.md b/docs/production/upgrade-or-modify.md
index a1619f6607..4435fd45f0 100644
--- a/docs/production/upgrade-or-modify.md
+++ b/docs/production/upgrade-or-modify.md
@@ -480,22 +480,34 @@ To upgrade the version of PostgreSQL on the Zulip server:
 
 1. Upgrade your server to the latest Zulip release (at least 3.0).
 
-2. Stop the server and take a backup:
+1. Stop the server, as the `zulip` user:
+
+    ```bash
+    # On Zulip before 4.0, use `supervisor stop all` instead
+    /home/zulip/deployments/current/scripts/stop-server
+    ```
+
+1. Take a backup, in case of any problems:
 
     ```bash
-    supervisorctl stop all
     /home/zulip/deployments/current/manage.py backup --output=/home/zulip/postgresql-upgrade.backup.tar.gz
     ```
 
-3. As root, run the database upgrade tool:
+1. As root, run the database upgrade tool:
 
     ```bash
     /home/zulip/deployments/current/scripts/setup/upgrade-postgresql
     ```
 
-`upgrade-postgresql` will have finished by restarting your Zulip server;
-you should now be able to navigate to its URL and confirm everything
-is working correctly.
+1. As the `zulip` user, start the server again:
+
+    ```bash
+    # On Zulip before 4.0, use `restart-server` instead of `start-server` instead
+    /home/zulip/deployments/current/scripts/start-server
+    ```
+
+You should now be able to navigate to the Zulip server's URL and
+confirm everything is working correctly.
 
 
 ## Modifying Zulip
diff --git a/puppet/zulip/manifests/supervisor.pp b/puppet/zulip/manifests/supervisor.pp
index 405855b1a7..536c498880 100644
--- a/puppet/zulip/manifests/supervisor.pp
+++ b/puppet/zulip/manifests/supervisor.pp
@@ -12,12 +12,15 @@ class zulip::supervisor {
   }
 
   $conf_dir = $zulip::common::supervisor_conf_dir
+  # lint:ignore:quoted_booleans
+  $should_purge = $facts['leave_supervisor'] != 'true'
+  # lint:endignore
   file { $conf_dir:
     ensure  => 'directory',
     require => Package['supervisor'],
     owner   => 'root',
     group   => 'root',
-    purge   => true,
+    purge   => $should_purge,
     recurse => true,
     notify  => Service[$supervisor_service],
   }
diff --git a/scripts/setup/upgrade-postgresql b/scripts/setup/upgrade-postgresql
index 64fa250912..61a0f1ae8b 100755
--- a/scripts/setup/upgrade-postgresql
+++ b/scripts/setup/upgrade-postgresql
@@ -34,7 +34,7 @@ fi
     crudini --set "$ZULIP_CONF" machine puppet_classes zulip::profile::base,zulip::postgresql_base
     touch "/usr/share/postgresql/$UPGRADE_TO/pgroonga_setup.sql.applied"
 
-    "$ZULIP_PATH"/scripts/zulip-puppet-apply -f --config "$ZULIP_CONF"
+    FACTER_LEAVE_SUPERVISOR=true "$ZULIP_PATH"/scripts/zulip-puppet-apply -f --config "$ZULIP_CONF"
     rm -rf "$TEMP_CONF_DIR"
 )