diff --git a/manifest.toml b/manifest.toml
index f321ac2..86293e4 100644
--- a/manifest.toml
+++ b/manifest.toml
@@ -56,6 +56,7 @@ ram.runtime = "50M"
     [resources.system_user]
 
     [resources.install_dir]
+    group = "www-data:r-x"
 
     [resources.permissions]
     main.url = "/"
diff --git a/scripts/backup b/scripts/backup
index 2223bdd..6f3e3bf 100755
--- a/scripts/backup
+++ b/scripts/backup
@@ -1,6 +1,5 @@
 #!/bin/bash
 
-# Keep this path for calling _common.sh inside the execution's context of backup and restore scripts
 source ../settings/scripts/_common.sh
 source /usr/share/yunohost/helpers
 
diff --git a/scripts/install b/scripts/install
index 51ef5a4..666bcf7 100755
--- a/scripts/install
+++ b/scripts/install
@@ -10,9 +10,6 @@ ynh_script_progression "Setting up source files..."
 
 ynh_setup_source --dest_dir="$install_dir/app"
 
-chmod -R "u=rX,g=rX,o=" "$install_dir"
-chown -R "$app:www-data" "$install_dir"
-
 #=================================================
 # ADD A CONFIGURATION
 #=================================================
diff --git a/scripts/restore b/scripts/restore
index de26cae..519dc16 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -1,6 +1,5 @@
 #!/bin/bash
 
-# Keep this path for calling _common.sh inside the execution's context of backup and restore scripts
 source ../settings/scripts/_common.sh
 source /usr/share/yunohost/helpers
 
@@ -11,9 +10,6 @@ ynh_script_progression "Restoring the app main directory..."
 
 ynh_restore "$install_dir"
 
-chmod -R "u=rX,g=rX,o=" "$install_dir"
-chown -R "$app:www-data" "$install_dir"
-
 chmod -R "u=rwX,g=,o=" "$install_dir/app/data"
 chown -R "$app:$app" "$install_dir/app/data"
 
diff --git a/scripts/upgrade b/scripts/upgrade
index d2cca9d..8b2ba97 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -22,10 +22,7 @@ fi
 #=================================================
 ynh_script_progression "Upgrading source files..."
 
-ynh_setup_source --dest_dir="$install_dir/app" --full_replace=1 --keep="app/data/_data_/_default_/configs/application.ini"
-
-chmod -R "u=rX,g=rX,o=" "$install_dir"
-chown -R "$app:www-data" "$install_dir"
+ynh_setup_source --dest_dir="$install_dir/app" --full_replace --keep="app/data/_data_/_default_/configs/application.ini"
 
 #=================================================
 # UPDATE A CONFIG FILE