diff --git a/conf/uwsgi-app@.service b/conf/uwsgi-app@.service
deleted file mode 100644
index f61228d..0000000
--- a/conf/uwsgi-app@.service
+++ /dev/null
@@ -1,20 +0,0 @@
-[Unit]
-Description=%i uWSGI app
-After=syslog.target
-
-[Service]
-RuntimeDirectory=%i
-ExecStart=/usr/bin/uwsgi \
-        --ini /etc/uwsgi/apps-available/%i.ini \
-        --socket /var/run/%i/app.socket \
-        --logto /var/log/uwsgi/%i/%i.log
-User=%i
-Group=www-data
-Restart=on-failure
-KillSignal=SIGQUIT
-Type=notify
-StandardError=syslog
-NotifyAccess=all
-
-[Install]
-WantedBy=multi-user.target
diff --git a/conf/uwsgi-app@override.service b/conf/uwsgi-app@override.service
new file mode 100644
index 0000000..eac7a8f
--- /dev/null
+++ b/conf/uwsgi-app@override.service
@@ -0,0 +1,2 @@
+[Unit]
+After=mysql.service
diff --git a/scripts/_common.sh b/scripts/_common.sh
index 6d7e3bb..03dfd56 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -6,7 +6,28 @@
 ynh_check_global_uwsgi_config () {
 	uwsgi --version || ynh_die "You need to add uwsgi (and appropriate plugin) as a dependency"
 
-	cp ../conf/uwsgi-app@.service /etc/systemd/system/uwsgi-app@.service
+	cat > /etc/systemd/system/uwsgi-app@.service <<EOF
+[Unit]
+Description=%i uWSGI app
+After=syslog.target
+
+[Service]
+RuntimeDirectory=%i
+ExecStart=/usr/bin/uwsgi \
+        --ini /etc/uwsgi/apps-available/%i.ini \
+        --socket /var/run/%i/app.socket \
+        --logto /var/log/uwsgi/%i/%i.log
+User=%i
+Group=www-data
+Restart=on-failure
+KillSignal=SIGQUIT
+Type=notify
+StandardError=syslog
+NotifyAccess=all
+
+[Install]
+WantedBy=multi-user.target
+EOF
 
 	systemctl daemon-reload
 }
@@ -26,6 +47,9 @@ ynh_check_global_uwsgi_config () {
 #   __PATH_2__    by $path_2
 #   __PORT_2__    by $port_2
 #
+# To be able to customise the settings of the systemd unit you can override the rules with the file "conf/uwsgi-app@override.service".
+# This file will be automatically placed on the good place
+#
 # usage: ynh_add_uwsgi_service
 #
 # to interact with your service: `systemctl <action> uwsgi-app@app`
@@ -70,8 +94,13 @@ ynh_add_uwsgi_service () {
 	chown $app:root /var/log/uwsgi/$app
 	chmod -R u=rwX,g=rX,o= /var/log/uwsgi/$app
 
+	# Setup specific Systemd rules if necessary
+	test -e ../conf/uwsgi-app@override.service && \
+		mkdir /etc/systemd/system/uwsgi-app@$app.service.d && \
+		cp ../conf/uwsgi-app@override.service /etc/systemd/system/uwsgi-app@$app.service.d/override.conf
+
 	systemctl daemon-reload
-	systemctl stop "uwsgi-app@$app.service"
+	systemctl stop "uwsgi-app@$app.service" || true
 	systemctl enable "uwsgi-app@$app.service"
 	systemctl start "uwsgi-app@$app.service"
 
@@ -91,5 +120,6 @@ ynh_remove_uwsgi_service () {
 
 		ynh_secure_remove "$finaluwsgiini"
 		ynh_secure_remove "/var/log/uwsgi/$app"
+		ynh_secure_remove "/etc/systemd/system/uwsgi-app@$app.service.d"
 	fi
 }
diff --git a/scripts/install b/scripts/install
index 1764eb3..a872873 100644
--- a/scripts/install
+++ b/scripts/install
@@ -114,7 +114,7 @@ ynh_system_user_create "$app" "$final_path"
 # pip installation
 #=================================================
 
-virtualenv "$final_path/local"
+virtualenv --python=$(which python2 python | head -n 1) "$final_path/local"
 # Init virtualenv
 (
 	set +o nounset
@@ -122,10 +122,10 @@ virtualenv "$final_path/local"
 	set -o nounset
 	cd "$final_path"
 	pip install --upgrade pip
-	pip install pyramid_chameleon
+	pip install --upgrade pyramid_chameleon
 	CFLAGS="-Wno-error -Wno-error=format-security" \
 		ARCHFLAGS="-Wno-error=unused-command-line-argument-hard-error-in-future" \
-		pip install --requirement "$final_path/requirements.txt"
+		pip install --upgrade --requirement "$final_path/requirements.txt"
 
 	python "$final_path/setup.py" develop
 
diff --git a/scripts/upgrade b/scripts/upgrade
index 84eb1d6..437b9f0 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -133,7 +133,7 @@ ynh_system_user_create "$app"
 # pip installation
 #=================================================
 
-virtualenv "$final_path/local"
+virtualenv --python=$(which python2 python | head -n 1) "$final_path/local"
 # Init virtualenv
 (
 	set +o nounset
@@ -141,10 +141,10 @@ virtualenv "$final_path/local"
 	set -o nounset
 	cd "$final_path"
 	pip install --upgrade pip
-	pip install pyramid_chameleon
+	pip install --upgrade pyramid_chameleon
 	CFLAGS="-Wno-error -Wno-error=format-security" \
 		ARCHFLAGS="-Wno-error=unused-command-line-argument-hard-error-in-future" \
-		pip install --requirement "$final_path/requirements.txt"
+		pip install --upgrade --requirement "$final_path/requirements.txt"
 
 	python "$final_path/setup.py" develop