diff --git a/README.md b/README.md
index 719593d5..c7b04601 100644
--- a/README.md
+++ b/README.md
@@ -32,8 +32,7 @@ improvements.
 
 Requirements
 ------------
-1.	PHP >= 5.4 (we still try to keep compatibility with php 5.3 as much as possible)
-        PHP 7.0 is explicitly supported. PHP 7.2 works as well, but may cause as yet unreported bugs.
+1.	PHP >= 7.4
 2.	MySQL/MariaDB server
 3.	[mbstring](http://www.php.net/manual/en/mbstring.installation.php) 
 4.	[PHP GD](http://www.php.net/manual/en/intro.image.php)
diff --git a/composer.json b/composer.json
index f48f7f55..a9e17c7e 100644
--- a/composer.json
+++ b/composer.json
@@ -2,10 +2,15 @@
     "name": "vichan-devel/vichan",
     "description": "vichan imageboard",
     "type": "project",
+    "config": {
+        "platform": {
+            "php": ">=7.4"
+        }
+    },
     "require": {
-        "ext-mbstring": ">=5.4",
-        "ext-gd": ">=5.4",
-        "ext-pdo": ">=5.4",
+        "ext-mbstring": ">=7.4",
+        "ext-gd": ">=7.4",
+        "ext-pdo": ">=7.4",
         "twig/twig": "^2.9",
         "phpmyadmin/twig-i18n-extension": "^4.0",
         "lifo/ip": "^1.0",
diff --git a/install.php b/install.php
index 1662ae77..b894f46c 100644
--- a/install.php
+++ b/install.php
@@ -729,10 +729,10 @@ if ($step == 0) {
 	$tests = array(
 		array(
 			'category' => 'PHP',
-			'name' => 'PHP ≥ 5.4',
+			'name' => 'PHP ≥ 7.4',
 			'result' => PHP_VERSION_ID >= 50400,
 			'required' => true,
-			'message' => 'vichan requires PHP 5.4 or better.',
+			'message' => 'vichan requires PHP 7.4 or better.',
 		),
 		array(
 			'category' => 'PHP',