diff --git a/README.md b/README.md
index d6a7457..5d8f603 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ Piwigo for YunoHost
 
 Extensions make Piwigo easily customizable. Icing on the cake, Piwigo is free and opensource.
 
-**Shipped version:** 2.8.3
+**Shipped version:** 2.8.5
 
 ![](http://piwigo.org/screenshots/homepage/piwigo-batch-manager.png)
 
diff --git a/scripts/_common.sh b/scripts/_common.sh
new file mode 100644
index 0000000..2eda7f1
--- /dev/null
+++ b/scripts/_common.sh
@@ -0,0 +1,21 @@
+#
+# Common variables
+#
+
+# Application version
+VERSION="2.8.5"
+
+# Remote URL to fetch application source archive
+APPLICATION_SOURCE_URL="http://piwigo.org/download/dlcounter.php?code=${VERSION}"
+
+# Download and extract application sources to the given directory
+# usage: extract_application_to DESTDIR
+extract_application() {
+  local DESTDIR=$1
+  archive="${DESTDIR}/application.zip"
+  wget -q -O "$archive" "$APPLICATION_SOURCE_URL" \
+|| ynh_die "Unable to download application archive"
+  sudo unzip -qq "$archive" -d "$DESTDIR" \
+    || ynh_die "Unable to extract application archive"
+  rm "$archive"
+}
\ No newline at end of file
diff --git a/scripts/install b/scripts/install
index 1ea12cd..ea94e17 100644
--- a/scripts/install
+++ b/scripts/install
@@ -5,6 +5,9 @@ set -eu
 
 app=$YNH_APP_INSTANCE_NAME
 
+# Source local helpers
+source ./_common.sh
+
 # Retrieve arguments
 domain=$YNH_APP_ARG_DOMAIN
 path=$YNH_APP_ARG_PATH
@@ -30,11 +33,8 @@ ynh_app_setting_set "$app" language "$language"
 sudo yunohost app checkurl "${domain}${path}" -a "$app" \
     || ynh_die "Path not available: ${domain}${path}"
 
-# Download sources 
-sudo wget -q http://piwigo.org/download/dlcounter.php?code=2.8.3 -O piwigo.zip
-
-# Uncompress
-sudo unzip -qq piwigo.zip -d ..
+# Download and extract application 
+extract_application ..
 
 # Copy source files
 src_path=/var/www/$app
diff --git a/scripts/upgrade b/scripts/upgrade
index bea56e5..7fe4279 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -1,13 +1,15 @@
 #!/bin/bash
-# =====================
-# TODO
-# =====================
 
 # Exit on command errors and treat unset variables as an error
 set -eu
 
+shopt -s extglob  # sets extended pattern matching options in the bash shell
+
 app=$YNH_APP_INSTANCE_NAME
 
+# Source local helpers
+source ./_common.sh
+
 # Source YunoHost helpers
 source /usr/share/yunohost/helpers
 
@@ -21,16 +23,13 @@ language=$(ynh_app_setting_get "$app" language)
 # Remove trailing "/" for next commands
 path=${path%/}
 
-# Download sources 
-sudo wget -q http://piwigo.org/download/dlcounter.php?code=2.8.3 -O piwigo.zip
-
-# Uncompress
-sudo unzip -qq piwigo.zip -d ../
+# Download and extract application 
+extract_application ..
 
 # Copy source files
 src_path=/var/www/$app
 sudo mkdir -p $src_path
-sudo cp -Raf ../piwigo/. $src_path
+sudo cp -Raf ../piwigo/!(upload) $src_path
 
 datapath=/home/yunohost.app/$app