diff --git a/src/mibew/install.php b/src/mibew/install.php
index 8fd8c0eb..5074c133 100644
--- a/src/mibew/install.php
+++ b/src/mibew/install.php
@@ -17,7 +17,7 @@
  * limitations under the License.
  */
 
-define('INSTALLATION_IN_PROGRESS', true);
+define('MAINTENANCE_MODE', 'install');
 
 // Initialize libraries
 require_once(dirname(__FILE__) . '/libs/init.php');
diff --git a/src/mibew/libs/common/locale.php b/src/mibew/libs/common/locale.php
index 1efde4bc..a176d5bf 100644
--- a/src/mibew/libs/common/locale.php
+++ b/src/mibew/libs/common/locale.php
@@ -57,8 +57,8 @@ function get_available_locales()
     static $available_locales = null;
 
     if (is_null($available_locales)) {
-        if (installation_in_progress()) {
-            // We cannot rely on the database during installation, thus we only
+        if (get_maintenance_mode() !== false) {
+            // We cannot rely on the database during maintenance, thus we only
             // can use discovered locales as available locales.
             $available_locales = discover_locales();
         } else {
@@ -728,9 +728,9 @@ function load_messages($locale)
     if (!isset($messages[$locale])) {
         $messages[$locale] = array();
 
-        if (installation_in_progress()) {
+        if (get_maintenance_mode() !== false) {
             // Load localized strings from files because we cannot rely on the
-            // database during installation.
+            // database during maintenance.
             $locale_file = MIBEW_FS_ROOT . "/locales/{$locale}/translation.po";
             $locale_data = read_locale_file($locale_file);
 
@@ -859,9 +859,9 @@ function get_localized_string($string, $locale)
 
     // The string is not localized, save it to the database to provide an
     // ability to translate it from the UI later. At the same time we cannot
-    // rely on the database during installation, thus we should check if the
-    // installation is in progress.
-    if (!installation_in_progress()) {
+    // rely on the database during maintenance, thus we should check the
+    // current system state.
+    if (get_maintenance_mode() === false) {
         save_message($locale, $string, $string);
     }
 
diff --git a/src/mibew/libs/common/misc.php b/src/mibew/libs/common/misc.php
index 53a91a85..ffecdb7a 100644
--- a/src/mibew/libs/common/misc.php
+++ b/src/mibew/libs/common/misc.php
@@ -23,15 +23,16 @@ function div($a, $b)
 }
 
 /**
- * Checks if currently processed script is installation script.
+ * Checks if the system is under maintenance and gets maintenance mode name.
  *
- * @return boolean
+ * @return boolean|string Name of maintenace mode or boolean false if the system
+ *   is not in maintenance mode.
  */
-function installation_in_progress()
+function get_maintenance_mode()
 {
-    if (!defined('INSTALLATION_IN_PROGRESS')) {
+    if (!defined('MAINTENANCE_MODE')) {
         return false;
     }
 
-    return INSTALLATION_IN_PROGRESS;
+    return MAINTENANCE_MODE;
 }
diff --git a/src/mibew/libs/init.php b/src/mibew/libs/init.php
index f2983943..a1acdded 100644
--- a/src/mibew/libs/init.php
+++ b/src/mibew/libs/init.php
@@ -69,7 +69,7 @@ if (function_exists("date_default_timezone_set")) {
     @date_default_timezone_set($timezone);
 }
 
-if (!installation_in_progress()) {
+if (get_maintenance_mode() === false) {
     // Initialize the database
     \Mibew\Database::initialize(
         $configs['database']['host'],