diff --git a/apps/advanced/environments/dev/backend/config/main-local.php b/apps/advanced/environments/dev/backend/config/main-local.php
index b2aaa3ad0d..43fc734c60 100644
--- a/apps/advanced/environments/dev/backend/config/main-local.php
+++ b/apps/advanced/environments/dev/backend/config/main-local.php
@@ -1,10 +1,12 @@
 <?php
-return [
-	'preload' => [
-		'debug',
-	],
-	'modules' => [
-		'debug' => 'yii\debug\Module',
-		'gii' => 'yii\gii\Module',
-	],
-];
+
+$config = [];
+
+if (YII_ENV_DEV) {
+	// configuration adjustments for 'dev' environment
+	$config['preload'][] = 'debug';
+	$config['modules']['debug'] = 'yii\debug\Module';
+	$config['modules']['gii'] = 'yii\gii\Module';
+}
+
+return $config;
diff --git a/apps/advanced/environments/dev/frontend/config/main-local.php b/apps/advanced/environments/dev/frontend/config/main-local.php
index 524c3a6395..43fc734c60 100644
--- a/apps/advanced/environments/dev/frontend/config/main-local.php
+++ b/apps/advanced/environments/dev/frontend/config/main-local.php
@@ -1,10 +1,12 @@
 <?php
-return [
-	'preload' => [
-		'debug',
-	],
-	'modules' => [
-				'debug' => 'yii\debug\Module',
-				'gii' => 'yii\gii\Module',
-	],
-];
+
+$config = [];
+
+if (YII_ENV_DEV) {
+	// configuration adjustments for 'dev' environment
+	$config['preload'][] = 'debug';
+	$config['modules']['debug'] = 'yii\debug\Module';
+	$config['modules']['gii'] = 'yii\gii\Module';
+}
+
+return $config;