diff --git a/conf/backup_method.j2 b/conf/backup_method.j2
index 369e1e6..e8511da 100644
--- a/conf/backup_method.j2
+++ b/conf/backup_method.j2
@@ -28,13 +28,23 @@ do_backup() {
     current_date=$(date +"%d_%m_%y_%H:%M")
     pushd $work_dir
     set +e
-    borg init -e repokey $repo >> $LOGFILE 2>> $ERRFILE
+    if borg init -e repokey $repo >> $LOGFILE 2>> $ERRFILE; then
+	    human_size=`echo $size | awk '{ suffix=" KMGT"; for(i=1; $1>1024 && i < length(suffix); i++) $1/=1024; print int($1) substr(suffix, i, 1), $3; }'`
+	    # Speed in Kbps
+	    speed=1000
+	    evaluated_time=$(($size / ($speed * 1000 / 8) / 3600))
+	    echo "Hello,
+
+Your first backup on $repo is starting. The backup size is evaluated to $human_size. If connectivity is 1Mbps between the 2 servers, it will take about $evaluated_time hour⋅s to transmit.
+
+This is an automated message from your beloved YunoHost server." | /usr/bin/mail.mailutils -a "Content-Type: text/plain; charset=UTF-8" -s "[YNH] First backup is starting" "root"
+    fi
     set -e
 
     borg create $repo::${name}_${current_date} ./ >> $LOGFILE 2>> $ERRFILE
     popd
 
-    borg prune $repo -P ${name} --keep-daily=7 --keep-weekly=8 --keep-monthly=12 >> $LOGFILE 2>> $ERRFILE
+    borg prune $repo -P ${name} --keep-hourly 2 --keep-daily=7 --keep-weekly=8 --keep-monthly=12 >> $LOGFILE 2>> $ERRFILE
 }
 
 do_mount() {
diff --git a/manifest.json b/manifest.json
index 30e15dc..9f238c2 100644
--- a/manifest.json
+++ b/manifest.json
@@ -6,7 +6,7 @@
         "en": "Backup your server with borg.",
         "fr": "Sauvegarder votre serveur avec borg."
     },
-    "version": "1.0",
+    "version": "1.0.1",
     "url": "https://borgbackup.readthedocs.io",
     "license": "BSD-3-Clause",
     "maintainer": {
@@ -15,7 +15,7 @@
         "url": "https://reflexlibre.net"
     },
     "requirements": {
-        "yunohost": ">= 2.7.2"
+        "yunohost": ">= 3.1"
     },
     "multi_instance": true,
     "services": [],
diff --git a/scripts/_common.sh b/scripts/_common.sh
index 1613437..769670d 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -6,7 +6,7 @@
 # App package root directory should be the parent folder
 PKG_DIR=$(cd ../; pwd)
 
-pkg_dependencies="python3-pip python3-dev libacl1-dev libssl-dev liblz4-dev python-jinja2"
+pkg_dependencies="python3-pip python3-dev libacl1-dev libssl-dev liblz4-dev python-jinja2 python3-setuptools"
 
 #=================================================
 # COMMON HELPERS
@@ -132,3 +132,69 @@ $(yunohost tools diagnosis | grep -B 100 "services:" | sed '/services:/d')"
 	# Send the email to the recipients
 	echo "$mail_message" | $mail_bin -a "Content-Type: text/plain; charset=UTF-8" -s "$mail_subject" "$recipients"
 }
+
+# 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', encoding='utf-8'))['$key'])"
+}
+
+
+# Checks the app version to upgrade with the existing app version and returns:
+# - UPGRADE_APP if the upstream app version has changed
+# - UPGRADE_PACKAGE if only the YunoHost package has changed
+#
+## It stops the current script without error if the package is up-to-date
+#
+# This helper should be used to avoid an upgrade of an app, or the upstream part
+# of it, when it's not needed
+#
+# To force an upgrade, even if the package is up to date,
+# you have to set the variable YNH_FORCE_UPGRADE before.
+# example: sudo YNH_FORCE_UPGRADE=1 yunohost app upgrade MyApp
+
+# usage: ynh_check_app_version_changed
+ynh_check_app_version_changed () {
+  local force_upgrade=${YNH_FORCE_UPGRADE:-0}
+  local package_check=${PACKAGE_CHECK_EXEC:-0}
+
+  # By default, upstream app version has changed
+  local return_value="UPGRADE_APP"
+
+  local current_version=$(ynh_read_manifest "/etc/yunohost/apps/$YNH_APP_INSTANCE_NAME/manifest.json" "version" || echo 1.0)
+  local current_upstream_version="${current_version/~ynh*/}"
+  local update_version=$(ynh_read_manifest "../manifest.json" "version" || echo 1.0)
+  local update_upstream_version="${update_version/~ynh*/}"
+
+  if [ "$current_version" == "$update_version" ] ; then
+      # Complete versions are the same
+      if [ "$force_upgrade" != "0" ]
+      then
+        echo "Upgrade forced by YNH_FORCE_UPGRADE." >&2
+        unset YNH_FORCE_UPGRADE
+      elif [ "$package_check" != "0" ]
+      then
+        echo "Upgrade forced for package check." >&2
+      else
+        ynh_die "Up-to-date, nothing to do" 0
+      fi
+  elif [ "$current_upstream_version" == "$update_upstream_version" ] ; then
+    # Upstream versions are the same, only YunoHost package versions differ
+    return_value="UPGRADE_PACKAGE"
+  fi
+  echo $return_value
+}
+
+
+ynh_install_backports () {
+    echo "deb http://httpredir.debian.org/debian stretch-backports main" > /etc/apt/sources.list.d/$app-stretch-backports.list
+}
+
+ynh_remove_backports () {
+    rm /etc/apt/sources.list.d/$app-stretch-backports.list
+}
diff --git a/scripts/install b/scripts/install
index 79f9105..a173fc5 100755
--- a/scripts/install
+++ b/scripts/install
@@ -29,12 +29,17 @@ ynh_export server ssh_user passphrase on_calendar conf data apps
 #=================================================
 ynh_save_args server ssh_user passphrase on_calendar conf data apps
 
+#=================================================
+# CONFIGURE BACKPORTS
+#=================================================
+# We need borg 1.1+ available only in backports
+ynh_install_backports
+
 #=================================================
 # STORE SETTINGS FROM MANIFEST
 #=================================================
 ynh_install_app_dependencies $pkg_dependencies
-pip3 install setuptools --upgrade
-pip3 install borgbackup
+ynh_package_install -t stretch-backports borgbackup
 
 #=================================================
 # ACTIVATE BACKUP METHODS
diff --git a/scripts/remove b/scripts/remove
index 4be7c3c..fefc270 100755
--- a/scripts/remove
+++ b/scripts/remove
@@ -20,6 +20,11 @@ app=$YNH_APP_INSTANCE_NAME
 #=================================================
 ynh_remove_app_dependencies
 
+#=================================================
+# REMOVE BACKPORTS
+#=================================================
+ynh_remove_backports
+
 #=================================================
 # REMOVE FILES
 #=================================================
diff --git a/scripts/restore b/scripts/restore
index 8f115d8..8b76574 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -31,11 +31,16 @@ server=$(ynh_app_setting_get $app server)
 ssh_user=$(ynh_app_setting_get $app ssh_user)
 
 #=================================================
-# STORE SETTINGS FROM MANIFEST
+# CONFIGURE BACKPORTS
+#=================================================
+# We need borg 1.1+ available only in backports
+ynh_install_backports
+
+#=================================================
+# INSTALL DEPENDENCIES
 #=================================================
 ynh_install_app_dependencies $pkg_dependencies
-pip3 install setuptools --upgrade
-pip3 install borgbackup
+ynh_package_install -t stretch-backports borgbackup
 
 #=================================================
 # ACTIVATE BACKUP METHODS
diff --git a/scripts/upgrade b/scripts/upgrade
index 35d72d2..a2f1c92 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -15,6 +15,11 @@ source /usr/share/yunohost/helpers
 
 app=$YNH_APP_INSTANCE_NAME
 
+#=================================================
+# CHECK IF AN UPGRADE IS NEEDED
+#=================================================
+ynh_check_app_version_changed
+
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================