diff --git a/composer.json b/composer.json
index 953ed53..e48b16e 100644
--- a/composer.json
+++ b/composer.json
@@ -3,7 +3,7 @@
 	"type": "phpbb-extension",
 	"description": "GDPR-ready consent manager for phpBB forums, providing category consent, deferred script and iframe loading, consent logging, and extension integration APIs.",
 	"homepage": "https://www.phpbb.com/",
-	"version": "1.0.1",
+	"version": "1.0.2-dev",
 	"keywords": ["phpbb", "extension", "gdpr", "consent", "cookies"],
 	"license": "GPL-2.0-only",
 	"authors": [
@@ -14,7 +14,7 @@
 	],
 	"require": {
 		"php": ">=7.2",
-		"composer/installers": "^1.0 || ^2.0",
+		"composer/installers": "~1.0",
 		"ext-dom": "*"
 	},
 	"require-dev": {
@@ -23,7 +23,7 @@
 	"extra": {
 		"display-name": "Consent Manager",
 		"soft-require": {
-			"phpbb/phpbb": ">=3.3.5"
+			"phpbb/phpbb": ">=3.3.5,<4.0.0@dev"
 		}
 	}
 }
diff --git a/ext.php b/ext.php
index 471a40c..055e3bd 100644
--- a/ext.php
+++ b/ext.php
@@ -39,7 +39,8 @@ public function is_enableable()
 	 */
 	protected function check_phpbb_version()
 	{
-		return phpbb_version_compare(PHPBB_VERSION, '3.3.5', '>=');
+		return phpbb_version_compare(PHPBB_VERSION, '3.3.5', '>=')
+			&& phpbb_version_compare(PHPBB_VERSION, '4.0.0-dev', '<');
 	}
 
 	/**
diff --git a/language/en/install.php b/language/en/install.php
index a34a654..8ba08f5 100644
--- a/language/en/install.php
+++ b/language/en/install.php
@@ -19,5 +19,5 @@
 }
 
 $lang = array_merge($lang, [
-	'CONSENTMANAGER_NOT_ENABLEABLE'	=> 'Consent Manager could not be enabled. The minimum requirements of phpBB 3.3.5 and/or PHP 7.2 were not satisfied.',
+	'CONSENTMANAGER_NOT_ENABLEABLE'	=> 'Consent Manager could not be enabled. The phpBB and PHP version requirements were not satisfied.',
 ]);