diff --git a/check_process b/check_process
index 755855f..b6f01b2 100644
--- a/check_process
+++ b/check_process
@@ -1,8 +1,8 @@
 ;; Full test
 	; Manifest
-		domain="domain.tld"	(DOMAIN)
-		path="/path"	(PATH)
-		is_public=1	(PUBLIC|public=1|private=0)
+		domain="domain.tld"
+		path="/path"
+		is_public=1
 	; Checks
 		pkg_linter=1
 		setup_sub_dir=1
@@ -13,21 +13,7 @@
 		upgrade=1
 		backup_restore=1
 		multi_instance=0
-		incorrect_path=1
-		port_already_use=0
 		change_url=0
-;;; Levels
-	Level 1=auto
-	Level 2=auto
-	Level 3=auto
-    # There is no user concept in ihatemoney
-	Level 4=1
-	Level 5=auto
-	Level 6=auto
-	Level 7=auto
-	Level 8=0
-	Level 9=0
-	Level 10=0
 ;;; Options
 Email=
 Notification=change
diff --git a/conf/nginx.conf b/conf/nginx.conf
index 3d13167..7c7358e 100644
--- a/conf/nginx.conf
+++ b/conf/nginx.conf
@@ -1,7 +1,10 @@
-location PATHTOCHANGE/static/ {
+location __PATH__/static/ {
     alias   /opt/yunohost/ihatemoney/venv/lib/pythonPYTHON_VERSION/site-packages/ihatemoney/static/;
 }
-location PATHTOCHANGE {
+
+#sub_path_only rewrite ^__PATH__$ __PATH__/ permanent;
+location __PATH__/ {
+
     # Force https.
     if ($scheme = http) {
         rewrite ^ https://$server_name$request_uri? permanent;
diff --git a/manifest.json b/manifest.json
index 5e1bd73..d672ea1 100644
--- a/manifest.json
+++ b/manifest.json
@@ -15,7 +15,7 @@
         "url": "https://jocelyn.delalande.fr"
     },
     "requirements": {
-        "yunohost": ">= 3.8"
+        "yunohost": ">= 4.2.4"
     },
     "multi_instance": false,
     "services": ["nginx", "mysql", "postfix"],
@@ -24,29 +24,17 @@
             {
                 "name": "domain",
                 "type": "domain",
-                "ask": {
-                    "en": "Choose a domain for ihatemoney",
-                    "fr": "Choisir un domaine pour ihatemoney"
-                },
                 "example": "example.com"
             },
             {
                 "name": "path",
                 "type": "path",
-                "ask": {
-                    "en": "Choose a path for ihatemoney",
-                    "fr": "Choisir un chemin pour ihatemoney"
-                },
                 "example": "/example",
                 "default": "/ihatemoney"
             },
             {
                 "name": "is_public",
                 "type": "boolean",
-                "ask": {
-                    "en": "Is it a public website ? (even if service is public, each project is protected by a password)",
-                    "fr": "Le service est-il public ? (même dans ce cas, chaque projet est protégé par un mot de passe)"
-                },
                 "default": true
             }
         ]
diff --git a/scripts/_common.sh b/scripts/_common.sh
index 8c54da6..8cc6629 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -1,3 +1,13 @@
+#=================================================
+# COMMON VARIABLES
+#=================================================
+
+# dependencies used by the app
+pkg_dependencies="python3-dev python3-virtualenv libffi-dev libssl-dev supervisor virtualenv"
+
+
+
+
 ### Constants
 
 supervisor_conf_path="/etc/supervisor/conf.d/ihatemoney.conf"
@@ -6,23 +16,6 @@ ihatemoney_conf_path="/etc/ihatemoney/ihatemoney.cfg"
 INSTALL_DIR="/opt/yunohost/ihatemoney"
 
 
-### Functions
-
-
-install_apt_dependencies() {
-    ynh_install_app_dependencies \
-        python3-dev \
-        python3-virtualenv \
-        libffi-dev \
-        libssl-dev \
-        supervisor \
-        virtualenv
-}
-
-create_unix_user() {
-    mkdir -p /opt/yunohost
-    useradd ihatemoney -d /opt/yunohost/ihatemoney/ --create-home || ynh_die "User creation failed"
-}
 
 create_system_dirs() {
     install -o ihatemoney -g ihatemoney -m 755 -d \
diff --git a/scripts/backup b/scripts/backup
index 7c21e82..b1cfaf8 100644
--- a/scripts/backup
+++ b/scripts/backup
@@ -1,25 +1,39 @@
 #!/bin/bash
 
-# Source YunoHost helpers
+#=================================================
+# GENERIC START
+#=================================================
+# IMPORT GENERIC HELPERS
+#=================================================
+
+# 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
 
+#=================================================
+# MANAGE SCRIPT FAILURE
+#=================================================
+
+ynh_clean_setup () {
+	### Remove this function if there's nothing to clean before calling the remove script.
+	true
+}
+# Exit if an error occurs during the execution of the script
 ynh_abort_if_errors
 
-# Get multi-instances specific variables
+#=================================================
+# LOAD SETTINGS
+#=================================================
+ynh_print_info --message="Loading installation settings..."
+
 app=$YNH_APP_INSTANCE_NAME
 
-# Set app specific variables
-dbname=$app
-dbuser=$app
+final_path=$(ynh_app_setting_get --app=$app --key=final_path)
+domain=$(ynh_app_setting_get --app=$app --key=domain)
+db_name=$(ynh_app_setting_get --app=$app --key=db_name)
 
 INSTALL_DIR=/opt/yunohost/ihatemoney
 
-# Retrieve app settings
-domain=$(ynh_app_setting_get "$app" domain)
-path=$(ynh_app_setting_get "$app" path)
-dbpass=$(ynh_app_setting_get "$app" mysqlpwd)
-
 # Backup conf files
 mkdir ./conf
 ynh_backup "/etc/nginx/conf.d/$domain.d/$app.conf"
@@ -27,8 +41,18 @@ ynh_backup "$gunicorn_conf_path"
 ynh_backup "$supervisor_conf_path"
 ynh_backup "$ihatemoney_conf_path"
 
-# Dump the database
-mysqldump -u "$dbuser" -p"$dbpass" --no-create-db "$dbname" > ./db.sql
-
 # Backup code and venv
 ynh_backup "$INSTALL_DIR" "install_dir"
+
+#=================================================
+# BACKUP THE MYSQL DATABASE
+#=================================================
+ynh_print_info --message="Backing up the MySQL database..."
+
+ynh_mysql_dump_db --database="$db_name" > db.sql
+
+#=================================================
+# END OF SCRIPT
+#=================================================
+
+ynh_print_info --message="Backup script completed for $app. (YunoHost will then actually copy those files to the archive)."
diff --git a/scripts/install b/scripts/install
index 8c1202c..4c389fd 100755
--- a/scripts/install
+++ b/scripts/install
@@ -1,14 +1,30 @@
 #!/bin/bash
 
-# Source YunoHost helpers
+#=================================================
+# GENERIC START
+#=================================================
+# IMPORT GENERIC HELPERS
+#=================================================
+
 source _common.sh
 source /usr/share/yunohost/helpers
 
+#=================================================
+# MANAGE SCRIPT FAILURE
+#=================================================
+
+ynh_abort_if_errors
+
+#=================================================
+# RETRIEVE ARGUMENTS FROM THE MANIFEST
+#=================================================
+
 # Retrieve arguments
 domain=$YNH_APP_ARG_DOMAIN
 path=$YNH_APP_ARG_PATH
 is_public=$YNH_APP_ARG_IS_PUBLIC
-app=ihatemoney
+
+app=$YNH_APP_INSTANCE_NAME
 
 # Database settings
 db_pwd=$(ynh_string_random)
@@ -20,12 +36,52 @@ secret_key=$(ynh_string_random --length 32)
 mails_sender="no-reply@${domain}"
 
 
-ynh_abort_if_errors
 
-ynh_webpath_register $app $domain $path
+#=================================================
+# CHECK IF THE APP CAN BE INSTALLED WITH THESE ARGS
+#=================================================
+ynh_script_progression --message="Validating installation parameters..." --weight=1
+
+final_path=/opt/yunohost/$app
+test ! -e "$final_path" || ynh_die --message="This path already contains a folder"
+
+# Register (book) web path
+ynh_webpath_register --app=$app --domain=$domain --path_url=$path_url
+
+#=================================================
+# STORE SETTINGS FROM MANIFEST
+#=================================================
+ynh_script_progression --message="Storing installation settings..." --weight=1
+
+ynh_app_setting_set --app=$app --key=domain --value=$domain
+ynh_app_setting_set --app=$app --key=path --value=$path_url
+
+#=================================================
+# INSTALL DEPENDENCIES
+#=================================================
+ynh_script_progression --message="Installing dependencies..." --weight=1
+
+ynh_install_app_dependencies $pkg_dependencies
+
+#=================================================
+# CREATE DEDICATED USER
+#=================================================
+ynh_script_progression --message="Configuring system user..." --weight=1
+
+# Create a system user
+ynh_system_user_create --username=$app --home_dir="$final_path"
+
+#=================================================
+# CREATE A MYSQL DATABASE
+#=================================================
+ynh_script_progression --message="Creating a MySQL database..." --time --weight=1
+
+db_name=$(ynh_sanitize_dbid --db_name=$app)
+db_user=$db_name
+ynh_app_setting_set --app=$app --key=db_name --value=$db_name
+ynh_mysql_setup_db --db_user=$db_user --db_name=$db_name
+
 
-# Configure database
-ynh_mysql_create_db "$db_name" "$db_user" "$db_pwd"
 
 # Save app settings
 ynh_app_setting_set "$app" mysqlpwd "$db_pwd"
@@ -62,17 +118,23 @@ sed -i "/APPLICATION_ROOT='\/'/d" ../conf/ihatemoney.cfg
 install -o ihatemoney -g ihatemoney -m 640 \
      ../conf/ihatemoney.cfg /etc/ihatemoney/ihatemoney.cfg
 
-# If app is public, add url to SSOWat conf as skipped_uris
-if [[ "$is_public" -ne 0 ]];
-then
-    ynh_app_setting_set $app unprotected_uris "/"
-fi
+#=================================================
+# NGINX CONFIGURATION
+#=================================================
+ynh_script_progression --message="Configuring NGINX web server..." --weight=1
+
+# Create a dedicated NGINX config
+ynh_add_nginx_config
+
+#=================================================
+# START SYSTEMD SERVICE
+#=================================================
+ynh_script_progression --message="Starting a systemd service..." --time --weight=1
+
+# Start a systemd service
+ynh_systemd_action --service_name=supervisor --action="start" --log_path="/var/log/$app/$app.log"
 
-# Configure Nginx
-configure_nginx "$domain" "$path"
 
-# Start backend
-systemctl start supervisor
 
 # Wait that gunicorn is ready to consider the install finished, that is to
 # avoid HTTP 502 right after installation
@@ -85,4 +147,26 @@ done
 # If socket not ready after 2 minutes waiting, ihatemoney will not work.
 test -S /tmp/budget.gunicorn.sock || ynh_die
 
-systemctl reload nginx
+#=================================================
+# SETUP SSOWAT
+#=================================================
+ynh_script_progression --message="Configuring permissions..." --weight=1
+
+# Make app public if necessary
+if [ $is_public -eq 1 ]
+then
+	ynh_permission_update --permission="main" --add="visitors"
+fi
+
+#=================================================
+# RELOAD NGINX
+#=================================================
+ynh_script_progression --message="Reloading NGINX web server..." --weight=1
+
+ynh_systemd_action --service_name=nginx --action=reload
+
+#=================================================
+# END OF SCRIPT
+#=================================================
+
+ynh_script_progression --message="Installation of $app completed" --last