diff --git a/check_process b/check_process
index 2033705..7d3022c 100644
--- a/check_process
+++ b/check_process
@@ -1,7 +1,7 @@
 ;; Test complet
 	; Manifest
-		domain="domain.tld"	(DOMAIN)
-		path="/path"	(PATH)
+		domain="domain.tld"
+		path="/path"
 		name="YunoJappix"
 		language="en"
 	; Checks
diff --git a/conf/app.src b/conf/app.src
index f465b4a..9977248 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -4,4 +4,3 @@ SOURCE_SUM_PRG=sha256sum
 SOURCE_FORMAT=zip
 SOURCE_IN_SUBDIR=true
 SOURCE_FILENAME=
-
diff --git a/manifest.json b/manifest.json
index d01b7c1..0282c73 100644
--- a/manifest.json
+++ b/manifest.json
@@ -14,7 +14,7 @@
         "email": "titoko@titoko.fr"
     },
     "requirements": {
-        "yunohost": ">> 4.1.7"
+        "yunohost": ">> 4.2.4"
     },
     "multi_instance": false,
     "services": [
diff --git a/scripts/install b/scripts/install
index b5b43eb..9a325a9 100644
--- a/scripts/install
+++ b/scripts/install
@@ -47,6 +47,14 @@ ynh_app_setting_set --app=$app --key=path --value=$path_url
 ynh_app_setting_set --app=$app --key=name --value=$name
 ynh_app_setting_set --app=$app --key=language --value=$language
 
+#=================================================
+# CREATE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Configuring system user..." --weight=1
+
+# Create a system user
+ynh_system_user_create --username=$app --home_dir="$final_path"
+
 #=================================================
 # DOWNLOAD, CHECK AND UNPACK SOURCE
 #=================================================
@@ -56,14 +64,9 @@ ynh_app_setting_set --app=$app --key=final_path --value=$final_path
 # Download, check integrity, uncompress and patch the source from app.src
 ynh_setup_source --dest_dir="$final_path"
 
-mkdir -p "$final_path/store/conf"
-cp ../conf/*.xml "$final_path/store/conf/"
-
-#=================================================
-# Set permissions to jappix directory
-#=================================================
-
-chown -R www-data: $final_path
+chmod 750 "$final_path"
+chmod -R o-rwx "$final_path"
+chown -R $app:www-data "$final_path"
 
 #=================================================
 # NGINX CONFIGURATION
@@ -77,8 +80,11 @@ ynh_add_nginx_config
 # Set Jappix configuration
 #=================================================
 
+mkdir -p "$final_path/store/conf"
+
 ynh_add_config --template="../conf/hosts.xml" --destination="$final_path/store/conf/hosts.xml"
 ynh_add_config --template="../conf/main.xml" --destination="$final_path/store/conf/main.xml"
+ynh_add_config --template="../conf/installed.xml" --destination="$final_path/store/conf/installed.xml"
 
 #=================================================
 # RELOAD NGINX
diff --git a/scripts/remove b/scripts/remove
index d75fc80..0865efe 100644
--- a/scripts/remove
+++ b/scripts/remove
@@ -35,6 +35,14 @@ ynh_script_progression --message="Removing NGINX web server configuration..." --
 # Remove the dedicated nginx config
 ynh_remove_nginx_config
 
+#=================================================
+# REMOVE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Removing the dedicated system user..." --weight=1
+
+# Delete a system user
+ynh_system_user_delete --username=$app
+
 #=================================================
 # END OF SCRIPT
 #=================================================
diff --git a/scripts/restore b/scripts/restore
index 359d7a9..b76fde8 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -44,6 +44,14 @@ test ! -d $final_path \
 
 ynh_restore_file --origin_path="/etc/nginx/conf.d/$domain.d/$app.conf"
 
+#=================================================
+# RECREATE THE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Recreating the dedicated system user..." --weight=1
+
+# Create the dedicated user (if not existing)
+ynh_system_user_create --username=$app --home_dir="$final_path"
+
 #=================================================
 # RESTORE THE APP MAIN DIR
 #=================================================
@@ -51,6 +59,10 @@ ynh_script_progression --message="Restoring the app main directory..." --weight=
 
 ynh_restore_file --origin_path=$final_path
 
+chmod 750 "$final_path"
+chmod -R o-rwx "$final_path"
+chown -R $app:www-data "$final_path"
+
 #=================================================
 # GENERIC FINALIZATION
 #=================================================
diff --git a/scripts/upgrade b/scripts/upgrade
index b6aa826..fc7d9f5 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -25,6 +25,12 @@ name=$(ynh_app_setting_get "$app" name)
 language=$(ynh_app_setting_get "$app" language)
 final_path=$(ynh_app_setting_get --app=$app --key=final_path)
 
+#=================================================
+# CHECK VERSION
+#=================================================
+
+upgrade_type=$(ynh_check_app_version_changed)
+
 #=================================================
 # ENSURE DOWNWARD COMPATIBILITY
 #=================================================
@@ -41,6 +47,26 @@ if [ -z "$name" ]; then
 	ynh_app_setting_set --app=$app --key=name --value=$name
 fi
 
+# If db_name doesn't exist, create it
+if [ -z "$final_path/store/conf" ]; then
+	mkdir -p "$final_path/store/conf"
+fi
+
+# Cleaning legacy permissions
+if ynh_legacy_permissions_exists; then
+	ynh_legacy_permissions_delete_all
+
+	ynh_app_setting_delete --app=$app --key=is_public
+fi
+
+#=================================================
+# CREATE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Making sure dedicated system user exists..." --weight=1
+
+# Create a dedicated user (if not existing)
+ynh_system_user_create --username=$app --home_dir="$final_path"
+
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================
@@ -55,28 +81,22 @@ ynh_clean_setup () {
 # Exit if an error occurs during the execution of the script
 ynh_abort_if_errors
 
-#=================================================
-# Copy files to the right place
-#=================================================
-
 #=================================================
 # DOWNLOAD, CHECK AND UNPACK SOURCE
 #=================================================
 ynh_script_progression --message="Setting up source files..." --weight=6
 
-ynh_setup_source --dest_dir=$final_path
+if [ "$upgrade_type" == "UPGRADE_APP" ]
+then
+	ynh_script_progression --message="Upgrading source files..." --weight=1
 
-mkdir -p "${final_path}/store/conf"
-cp ../conf/*.xml "${final_path}/store/conf/"
+	# Download, check integrity, uncompress and patch the source from app.src
+	ynh_setup_source --dest_dir="$final_path"
+fi
 
-#=================================================
-# GENERIC FINALIZATION
-#=================================================
-# SECURE FILES AND DIRECTORIES
-#=================================================
-
-# Set permissions to jappix directory
-chown -R www-data: $final_path
+chmod 750 "$final_path"
+chmod -R o-rwx "$final_path"
+chown -R $app:www-data "$final_path"
 
 #=================================================
 # NGINX CONFIGURATION
@@ -92,6 +112,7 @@ ynh_add_nginx_config
 
 ynh_add_config --template="../conf/hosts.xml" --destination="$final_path/store/conf/hosts.xml"
 ynh_add_config --template="../conf/main.xml" --destination="$final_path/store/conf/main.xml"
+ynh_add_config --template="../conf/installed.xml" --destination="$final_path/store/conf/installed.xml"
 
 #=================================================
 # RELOAD NGINX