diff --git a/manifest.json b/manifest.json
index 341f88a..315067c 100644
--- a/manifest.json
+++ b/manifest.json
@@ -6,7 +6,7 @@
         "en": "Manage PostgreSQL databases over the web",
         "fr": "Application web de gestion des bases de données PostgreSQL"
     },
-    "version": "4-2.1",
+    "version": "4-2.1~ynh1",
     "url": "https://www.pgadmin.org",
     "license": "PostgreSQL",
     "maintainer": {
diff --git a/scripts/_common.sh b/scripts/_common.sh
index bc30839..da28201 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -1,18 +1,20 @@
+#=================================================
+# SET ALL CONSTANTS
+#=================================================
+
 app=$YNH_APP_INSTANCE_NAME
 final_path=/opt/yunohost/$app
 pgadmin_user="pgadmin"
 
-get_app_version_from_json() {
-   manifest_path="../manifest.json"
-    if [ ! -e "$manifest_path" ]; then
-    	manifest_path="../settings/manifest.json"	# Into the restore script, the manifest is not at the same place
-    fi
-    echo $(grep '\"version\": ' "$manifest_path" | cut -d '"' -f 4)	# Retrieve the version number in the manifest file.
-}
-APP_VERSION=$(get_app_version_from_json)
+[[ -e "../settings/manifest.json" ]] || [[ -e "../manifest.json" ]] && \
+    APP_VERSION=$(ynh_app_upstream_version)
 app_main_version=$(echo $APP_VERSION | cut -d'-' -f1)
 app_sub_version=$(echo $APP_VERSION | cut -d'-' -f2)
 
+#=================================================
+# DEFINE ALL COMMON FONCTIONS
+#=================================================
+
 install_dependance() {
 	ynh_install_app_dependencies python-pip build-essential python-dev python-virtualenv postgresql uwsgi uwsgi-plugin-python expect
 }
diff --git a/scripts/backup b/scripts/backup
index bcabd7c..463c493 100644
--- a/scripts/backup
+++ b/scripts/backup
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#=================================================
+# GENERIC START
+#=================================================
+
 # IMPORT GENERIC HELPERS
 source /usr/share/yunohost/helpers
 
@@ -7,14 +11,18 @@ source /usr/share/yunohost/helpers
 ynh_abort_if_errors
 
 # Import common cmd
+source ../settings/scripts/experimental_helper.sh
 source ../settings/scripts/_common.sh
-source ../settings/scripts/psql.sh
 
 # LOAD SETTINGS
 final_path=$(ynh_app_setting_get $app final_path)
 domain=$(ynh_app_setting_get $app domain)
 db_name=$(ynh_app_setting_get $app db_name)
 
+#=================================================
+# STANDARD BACKUP STEPS
+#=================================================
+
 # BACKUP THE APP MAIN DIR
 ynh_backup "$final_path"
 
diff --git a/scripts/change_url b/scripts/change_url
index 10e793a..926c4bd 100644
--- a/scripts/change_url
+++ b/scripts/change_url
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#=================================================
+# GENERIC START
+#=================================================
+
 # Source YunoHost helpers
 source /usr/share/yunohost/helpers
 
@@ -7,6 +11,7 @@ source /usr/share/yunohost/helpers
 ynh_abort_if_errors
 
 # Import common cmd
+source ./experimental_helper.sh
 source ./_common.sh
 
 # Retrive arguments
@@ -37,7 +42,10 @@ then
 	change_path=1
 fi
 
+#=================================================
 # STANDARD MODIFICATIONS
+#=================================================
+
 # MODIFY URL IN NGINX CONF
 nginx_conf_path=/etc/nginx/conf.d/$old_domain.d/$app.conf
 
diff --git a/scripts/psql.sh b/scripts/experimental_helper.sh
similarity index 71%
rename from scripts/psql.sh
rename to scripts/experimental_helper.sh
index 9789a29..43b7df1 100644
--- a/scripts/psql.sh
+++ b/scripts/experimental_helper.sh
@@ -145,4 +145,51 @@ ynh_psql_test_if_first_run() {
 		systemctl enable postgresql
 		systemctl reload postgresql
 	fi
+}
+
+#=================================================
+# OTHERS HELPERS
+#=================================================
+
+# Read the value of a key in a ynh manifest file
+#
+# usage: ynh_read_manifest manifest key
+# | arg: manifest - Path of the manifest to read
+# | arg: key - Name of the key to find
+ynh_read_manifest () {
+	manifest="$1"
+	key="$2"
+	python3 -c "import sys, json;print(json.load(open('$manifest'))['$key'])"
+}
+
+# Read the upstream version from the manifest 
+# The version number in the manifest is defined by <upstreamversion>~ynh<packageversion>
+# For example : 4.3-2~ynh3
+# This include the number before ~ynh
+# In the last example it return 4.3-2
+#
+# usage: ynh_app_upstream_version
+ynh_app_upstream_version () {
+    manifest_path="../manifest.json"
+    if [ ! -e "$manifest_path" ]; then
+        manifest_path="../settings/manifest.json"	# Into the restore script, the manifest is not at the same place
+    fi
+    version_key=$(ynh_read_manifest "$manifest_path" "version")
+    echo "${version_key/~ynh*/}"
+}
+
+# Read package version from the manifest
+# The version number in the manifest is defined by <upstreamversion>~ynh<packageversion>
+# For example : 4.3-2~ynh3
+# This include the number after ~ynh
+# In the last example it return 3
+#
+# usage: ynh_app_package_version
+ynh_app_package_version () {
+    manifest_path="../manifest.json"
+    if [ ! -e "$manifest_path" ]; then
+        manifest_path="../settings/manifest.json"	# Into the restore script, the manifest is not at the same place
+    fi
+    version_key=$(ynh_read_manifest "$manifest_path" "version")
+    echo "${version_key/*~ynh/}"
 }
\ No newline at end of file
diff --git a/scripts/install b/scripts/install
index 43cf863..c8bbf7b 100644
--- a/scripts/install
+++ b/scripts/install
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#=================================================
+# GENERIC START
+#=================================================
+
 # IMPORT GENERIC HELPERS
 source /usr/share/yunohost/helpers
 
@@ -7,8 +11,8 @@ source /usr/share/yunohost/helpers
 ynh_abort_if_errors
 
 # Import common cmd
+source ./experimental_helper.sh
 source ./_common.sh
-source ./psql.sh
 
 # RETRIEVE ARGUMENTS FROM THE MANIFEST
 domain=$YNH_APP_ARG_DOMAIN
@@ -40,6 +44,10 @@ ynh_app_setting_set $app admin_pwd "$admin_pwd"
 ynh_app_setting_set $app db_user "$db_user"
 ynh_app_setting_set $app db_pwd "$db_pwd"
 
+#=================================================
+# STANDARD MODIFICATIONS
+#=================================================
+
 # Install dependance
 install_dependance
 
@@ -77,6 +85,10 @@ su --command="psql -c\"CREATE USER ${db_user} WITH PASSWORD '${db_pwd}' SUPERUSE
 $final_path/bin/python2.7 config_database.py "$db_user" "$db_pwd"
 deactivate
 
+#=================================================
+# GENERIC FINALIZATION
+#=================================================
+
 # Set permission after initialisation
 set_permission
 
diff --git a/scripts/remove b/scripts/remove
index 5f5cb07..599c879 100644
--- a/scripts/remove
+++ b/scripts/remove
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#=================================================
+# GENERIC START
+#=================================================
+
 # Source YunoHost helpers
 source /usr/share/yunohost/helpers
 
@@ -7,14 +11,18 @@ source /usr/share/yunohost/helpers
 set -u
 
 # Import common cmd
+source ./experimental_helper.sh
 source ./_common.sh
-source ./psql.sh
 
 # LOAD SETTINGS
 domain=$(ynh_app_setting_get $app domain)
 db_name=$(ynh_app_setting_get $app db_name)
 db_user="pgadmin"
 
+#=================================================
+# STANDARD REMOVE
+#=================================================
+
 # Remove db user
 ynh_psql_drop_user $db_user
 
diff --git a/scripts/restore b/scripts/restore
index 752bf55..8799944 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#=================================================
+# GENERIC START
+#=================================================
+
 # IMPORT GENERIC HELPERS
 source /usr/share/yunohost/helpers
 
@@ -7,8 +11,8 @@ source /usr/share/yunohost/helpers
 ynh_abort_if_errors
 
 # Import common cmd
+source ../settings/scripts/experimental_helper.sh
 source ../settings/scripts/_common.sh
-source ../settings/scripts/psql.sh
 
 # LOAD SETTINGS
 domain=$(ynh_app_setting_get $app domain)
@@ -19,6 +23,10 @@ db_name=$(ynh_app_setting_get $app db_name)
 db_user=$(ynh_app_setting_get $app db_user)
 db_pwd=$(ynh_app_setting_get $app db_pwd)
 
+#=================================================
+# STANDARD RESTORATION STEPS
+#=================================================
+
 # Install dependance
 install_dependance
 
@@ -32,6 +40,10 @@ ynh_restore
 ynh_psql_test_if_first_run
 su --command="psql -c\"CREATE USER ${db_user} WITH PASSWORD '${db_pwd}' SUPERUSER CREATEDB CREATEROLE REPLICATION\"" postgres
 
+#=================================================
+# GENERIC FINALIZATION
+#=================================================
+
 # Set the permission
 set_permission
 
diff --git a/scripts/upgrade b/scripts/upgrade
index ec24630..89e32e7 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#=================================================
+# GENERIC START
+#=================================================
+
 # IMPORT GENERIC HELPERS
 source /usr/share/yunohost/helpers
 
@@ -7,8 +11,8 @@ source /usr/share/yunohost/helpers
 ynh_abort_if_errors
 
 # Import common cmd
+source ./experimental_helper.sh
 source ./_common.sh
-source ./psql.sh
 
 # LOAD SETTINGS
 domain=$(ynh_app_setting_get $app domain)
@@ -21,6 +25,10 @@ ynh_clean_setup () {
 	ynh_restore_upgradebackup	# restore it if the upgrade fails
 }
 
+#=================================================
+# STANDARD UPGRADE STEPS
+#=================================================
+
 # Download, check integrity, uncompress and patch the source from app.src
 install_source
 
@@ -30,6 +38,10 @@ config_pgadmin
 # Config uwsgi
 config_uwsgi
 
+#=================================================
+# GENERIC FINALIZATION
+#=================================================
+
 # Set permission after initialisation
 set_permission