diff --git a/INSTALL.md b/INSTALL.md
index 5dbc509..b627bc9 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -10,7 +10,7 @@ check the options and adjust them as you see fit.
 
 ### Requirements
 
-- PHP version 5.3 or above
+- PHP version 5.4 or above
 - _one_ of the following sources of cryptographically safe randomness is required:
   - PHP 7 or higher
   - [Libsodium](https://download.libsodium.org/libsodium/content/installation/) and it's [PHP extension](https://paragonie.com/book/pecl-libsodium/read/00-intro.md#installing-libsodium)
diff --git a/composer.json b/composer.json
index 632bf2b..4248b5f 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         }
     ],
     "require": {
-        "php": "^5.3.0 || ^7.0",
+        "php": "^5.4.0 || ^7.0",
         "paragonie/random_compat": "2.0.4",
         "yzalis/identicon": "1.1.0"
     },
diff --git a/i18n/de.json b/i18n/de.json
index 9959e71..7974d77 100644
--- a/i18n/de.json
+++ b/i18n/de.json
@@ -7,8 +7,8 @@
     "en": "de",
     "Paste does not exist, has expired or has been deleted.":
         "Diesen Text gibt es nicht, er ist abgelaufen oder wurde gelöscht.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "%s benötigt PHP 5.3.0 oder höher, um zu funktionieren. Sorry.",
+    "%s requires php %s or above to work. Sorry.":
+        "%s benötigt PHP %s oder höher, um zu funktionieren. Sorry.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s benötigt den Konfigurationsabschnitt [%s] in der Konfigurationsdatei um zu funktionieren.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/es.json b/i18n/es.json
index 1e2fd48..e957c8f 100644
--- a/i18n/es.json
+++ b/i18n/es.json
@@ -7,8 +7,8 @@
     "en": "es",
     "Paste does not exist, has expired or has been deleted.":
         "El texto no existe, ha caducado o ha sido eliminado.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "%s requiere php 5.3.0 o superior para funcionar. Lo siento.",
+    "%s requires php %s or above to work. Sorry.":
+        "%s requiere php %s o superior para funcionar. Lo siento.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s requiere que la sección de configuración [%s] esté presente en el archivo de configuración.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/fr.json b/i18n/fr.json
index 61e0a3c..35cfd65 100644
--- a/i18n/fr.json
+++ b/i18n/fr.json
@@ -7,8 +7,8 @@
     "en": "fr",
     "Paste does not exist, has expired or has been deleted.":
         "Le paste n'existe pas, a expiré, ou a été supprimé.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "Désolé, %s nécessite php 5.3.0 ou supérieur pour fonctionner.",
+    "%s requires php %s or above to work. Sorry.":
+        "Désolé, %s nécessite php %s ou supérieur pour fonctionner.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s a besoin de la section de configuration [%s] dans le fichier de configuration pour fonctionner.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/it.json b/i18n/it.json
index 30a80e9..dc56fa7 100644
--- a/i18n/it.json
+++ b/i18n/it.json
@@ -7,8 +7,8 @@
     "en": "it",
     "Paste does not exist, has expired or has been deleted.":
         "Questo messaggio non esiste, è scaduto o è stato cancellato.",
-    "%s requires php 5.4.0 or above to work. Sorry.":
-        "%s richiede php 5.4.0 o superiore per funzionare. Ci spiace.",
+    "%s requires php %s or above to work. Sorry.":
+        "%s richiede php %s o superiore per funzionare. Ci spiace.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s richiede la presenza della sezione [%s] nei file di configurazione.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/no.json b/i18n/no.json
index 4d92cc8..fd56583 100644
--- a/i18n/no.json
+++ b/i18n/no.json
@@ -7,8 +7,8 @@
     "en": "no",
     "Paste does not exist, has expired or has been deleted.":
         "Innlegget eksisterer ikke, er utløpt eller har blitt slettet.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "Beklager, %s krever php 5.3.0 eller nyere for å kjøre.",
+    "%s requires php %s or above to work. Sorry.":
+        "Beklager, %s krever php %s eller nyere for å kjøre.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s krever konfigurasjonsdel [%s] å være til stede i konfigurasjonsfilen .",
     "Please wait %d seconds between each post.":
diff --git a/i18n/oc.json b/i18n/oc.json
index a29bce0..b6b449d 100644
--- a/i18n/oc.json
+++ b/i18n/oc.json
@@ -7,8 +7,8 @@
     "en": "oc",
     "Paste does not exist, has expired or has been deleted.":
         "Lo tèxte existís pas, a expirat, o es estat suprimit.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "O planhèm, %s necessita php 5.3.0 o superior per foncionar.",
+    "%s requires php %s or above to work. Sorry.":
+        "O planhèm, %s necessita php %s o superior per foncionar.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s fa besonh de la seccion de configuracion [%s] dins lo fichièr de configuracion per foncionar.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/pl.json b/i18n/pl.json
index b9cc8f2..9955498 100644
--- a/i18n/pl.json
+++ b/i18n/pl.json
@@ -7,8 +7,8 @@
     "en": "pl",
     "Paste does not exist, has expired or has been deleted.":
         "Wklejka nie istnieje, wygasła albo została usunięta.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "%s wymaga PHP w wersji 5.3.0 lub nowszej, sorry.",
+    "%s requires php %s or above to work. Sorry.":
+        "%s wymaga PHP w wersji %s lub nowszej, sorry.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s wymaga obecności sekcji [%s] w pliku konfiguracyjnym.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/pt.json b/i18n/pt.json
index e00a4a1..ab45952 100644
--- a/i18n/pt.json
+++ b/i18n/pt.json
@@ -7,8 +7,8 @@
     "en": "pt",
     "Paste does not exist, has expired or has been deleted.":
         "A cópia não existe, expirou ou já foi excluída.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "%s requer php 5.3.0 ou superior para funcionar. Desculpa.",
+    "%s requires php %s or above to work. Sorry.":
+        "%s requer php %s ou superior para funcionar. Desculpa.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s requer que a seção de configuração [% s] esteja no arquivo de configuração.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/sl.json b/i18n/sl.json
index 2df2608..00b0970 100644
--- a/i18n/sl.json
+++ b/i18n/sl.json
@@ -7,8 +7,8 @@
     "en": "sl",
     "Paste does not exist, has expired or has been deleted.":
         "Prilepek ne obstaja, mu je potekla življenjska doba, ali pa je izbrisan.",
-    "%s requires php 5.3.0 or above to work. Sorry.":
-        "Oprosti, %s za delovanje potrebuje vsaj php 5.3.0.",
+    "%s requires php %s or above to work. Sorry.":
+        "Oprosti, %s za delovanje potrebuje vsaj php %s.",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s potrebuje sekcijo konfiguracij [%s] v konfiguracijski datoteki.",
     "Please wait %d seconds between each post.":
diff --git a/i18n/zh.json b/i18n/zh.json
index d779c04..5fcaf3d 100644
--- a/i18n/zh.json
+++ b/i18n/zh.json
@@ -7,8 +7,8 @@
     "en": "zh",
     "Paste does not exist, has expired or has been deleted.":
         "粘贴不存在，已过期或者已被删除。",
-    "%s requires php 5.4.0 or above to work. Sorry.":
-        "%s需要工作于PHP 5.4.0及以上版本，抱歉。",
+    "%s requires php %s or above to work. Sorry.":
+        "%s需要工作于PHP %s及以上版本，抱歉。",
     "%s requires configuration section [%s] to be present in configuration file.":
         "%s需要设置配置文件中 [%s] 的部分。",
     "Please wait %d seconds between each post.":
diff --git a/lib/PrivateBin.php b/lib/PrivateBin.php
index fb3e523..e874015 100644
--- a/lib/PrivateBin.php
+++ b/lib/PrivateBin.php
@@ -30,6 +30,13 @@ class PrivateBin
      */
     const VERSION = '1.1';
 
+    /**
+     * minimal required PHP version
+     *
+     * @const string
+     */
+    const MIN_PHP_VERSION = '5.4.0';
+
     /**
      * show the same error message if the paste expired or does not exist
      *
@@ -120,8 +127,8 @@ class PrivateBin
      */
     public function __construct()
     {
-        if (version_compare(PHP_VERSION, '5.4.0') < 0) {
-            throw new Exception(I18n::_('%s requires php 5.4.0 or above to work. Sorry.', I18n::_('PrivateBin')), 1);
+        if (version_compare(PHP_VERSION, self::MIN_PHP_VERSION) < 0) {
+            throw new Exception(I18n::_('%s requires php %s or above to work. Sorry.', I18n::_('PrivateBin'), self::MIN_PHP_VERSION), 1);
         }
         if (strlen(PATH) < 0 && substr(PATH, -1) !== DIRECTORY_SEPARATOR) {
             throw new Exception(I18n::_('%s requires the PATH to end in a "%s". Please update the PATH in your index.php.', I18n::_('PrivateBin'), DIRECTORY_SEPARATOR), 5);