diff --git a/scripts/backup b/scripts/backup
index 50269b2..7a956c3 100644
--- a/scripts/backup
+++ b/scripts/backup
@@ -3,11 +3,20 @@
 # causes the shell to exit if any subcommand or pipeline returns a non-zero status
 set -e
 
-# The parameter $1 is the backup directory location dedicated to the app
-backup_dir=$1
+# Source YNH helpers
+. /usr/share/yunohost/helpers
 
-# The last parameter is the id of the app instance
-app=${!#}
+# This is a multi-instance app, meaning it can be installed several times independently
+# The id of the app as stated in the manifest is available as $YNH_APP_ID
+# The instance number is available as $YNH_APP_INSTANCE_NUMBER (equals "1", "2", ...)
+# The app instance name is available as $YNH_APP_INSTANCE_NAME
+#    - the first time the app is installed, YNH_APP_INSTANCE_NAME = ynhexample
+#    - the second time the app is installed, YNH_APP_INSTANCE_NAME = ynhexample__2
+#    - ynhexample__{N} for the subsequent installations, with N=3,4, ...
+# The app instance name is probably what you are interested the most, since this is
+# guaranteed to be unique. This is a good unique identifier to define installation path,
+# db names, ...
+app=$YNH_APP_INSTANCE_NAME
 
 domain=$(sudo yunohost app setting $app domain)
 path=$(sudo yunohost app setting $app path)