diff --git a/scripts/upgrade b/scripts/upgrade
index 243e85b..c4a8cf4 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -16,13 +16,13 @@ ynh_script_progression --message="Loading installation settings..." --time --wei
 
 app=$YNH_APP_INSTANCE_NAME
 
-domain=$(ynh_app_setting_get --app=$app --key=domain)
-path_url=$(ynh_app_setting_get --app=$app --key=path)
-admin=$(ynh_app_setting_get --app=$app --key=admin)
-is_public=$(ynh_app_setting_get --app=$app --key=is_public)
-final_path=$(ynh_app_setting_get --app=$app --key=final_path)
-language=$(ynh_app_setting_get --app=$app --key=language)
-db_name=$(ynh_app_setting_get --app=$app --key=db_name)
+domain=$(ynh_app_setting_get --app="$app" --key=domain)
+path_url=$(ynh_app_setting_get --app="$app" --key=path)
+admin=$(ynh_app_setting_get --app="$app" --key=admin)
+is_public=$(ynh_app_setting_get --app="$app" --key=is_public)
+final_path=$(ynh_app_setting_get --app="$app" --key=final_path)
+language=$(ynh_app_setting_get --app="$app" --key=language)
+db_name=$(ynh_app_setting_get --app="$app" --key=db_name)
 
 #=================================================
 # CHECK VERSION
@@ -43,23 +43,23 @@ ynh_script_progression --message="Ensuring downward compatibility..." --time --w
 
 # Fix is_public as a boolean value
 if [ "$is_public" = "Yes" ]; then
-	ynh_app_setting_set --app=$app --key=is_public --value=1
+	ynh_app_setting_set --app="$app" --key=is_public --value=1
 	is_public=1
 elif [ "$is_public" = "No" ]; then
-	ynh_app_setting_set --app=$app --key=is_public --value=0
+	ynh_app_setting_set --app="$app" --key=is_public --value=0
 	is_public=0
 fi
 
 # If db_name doesn't exist, create it
 if [ -z "$db_name" ]; then
-	db_name=$(ynh_sanitize_dbid --db_name=$app)
-	ynh_app_setting_set --app=$app --key=db_name --value=$db_name
+	db_name=$(ynh_sanitize_dbid --db_name="$app")
+	ynh_app_setting_set --app="$app" --key=db_name --value="$db_name"
 fi
 
 # If final_path doesn't exist, create it
 if [ -z "$final_path" ]; then
 	final_path=/var/www/$app
-	ynh_app_setting_set --app=$app --key=final_path --value=$final_path
+	ynh_app_setting_set --app="$app" --key=final_path --value="$final_path"
 fi
 
 #=================================================
@@ -86,7 +86,7 @@ ynh_abort_if_errors
 # instead of /foo ....
 # If nobody installed your app before 2.7, then you may
 # safely remove this line
-path_url=$(ynh_normalize_url_path --path_url=$path_url)
+path_url=$(ynh_normalize_url_path --path_url="$path_url")
 
 #=================================================
 # STANDARD UPGRADE STEPS
@@ -95,7 +95,7 @@ path_url=$(ynh_normalize_url_path --path_url=$path_url)
 #=================================================
 ynh_script_progression --message="Stopping a systemd service..." --time --weight=1
 
-ynh_systemd_action --service_name=$app --action="stop" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="stop" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # DOWNLOAD, CHECK AND UNPACK SOURCE
@@ -122,7 +122,7 @@ ynh_add_nginx_config
 #=================================================
 ynh_script_progression --message="Upgrading dependencies..." --time --weight=1
 
-ynh_install_app_dependencies $pkg_dependencies
+ynh_install_app_dependencies "$pkg_dependencies"
 
 #=================================================
 # CREATE DEDICATED USER
@@ -130,7 +130,7 @@ ynh_install_app_dependencies $pkg_dependencies
 ynh_script_progression --message="Making sure dedicated system user exists..." --time --weight=1
 
 # Create a dedicated user (if not existing)
-ynh_system_user_create --username=$app
+ynh_system_user_create --username="$app"
 
 #=================================================
 # PHP-FPM CONFIGURATION
@@ -187,7 +187,7 @@ ynh_add_fail2ban_config --logpath="/var/log/nginx/${domain}-error.log" --failreg
 #=================================================
 
 # Set permissions on app files
-chown -R root: $final_path
+chown -R root: "$final_path"
 
 #=================================================
 # SETUP SSOWAT
@@ -198,7 +198,7 @@ ynh_script_progression --message="Upgrading SSOwat configuration..." --time --we
 if [ $is_public -eq 1 ]
 then
 	# unprotected_uris allows SSO credentials to be passed anyway
-	ynh_app_setting_set --app=$app --key=unprotected_uris --value="/"
+	ynh_app_setting_set --app="$app" --key=unprotected_uris --value="/"
 fi
 
 #=================================================
@@ -206,7 +206,7 @@ fi
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --time --weight=1
 
-ynh_systemd_action --service_name=$app --action="start" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="start" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # RELOAD NGINX