diff --git a/scripts/_common.sh b/scripts/_common.sh
index 055ee17..be9dd31 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -13,16 +13,25 @@ is_url_handled() {
   [[ ! ${output[0]} =~ \/yunohost\/sso\/ && ${output[1]} != 404 ]]
 }
 
-is_url_handled_custom() {
-  local output=($(curl -k -s -o /dev/null \
-      -w 'x%{redirect_url} %{http_code}' "$1"))
-  echo "¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤"
-  echo "contenu variable 'output' : $output"
-  echo "¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤"
-  # It's handled if it does not redirect to the SSO nor return 404
-  [[ ! ${output[0]} =~ \/yunohost\/sso\/ && ${output[1]} != 404 ]]
-  #[[ ! ${output[0]} =~ \/yunohost\/sso\/ ]] && [[ ${output[1]} != 404 ]]
-  #[[ ! ${output[0]} =~ \/yunohost\/sso\/ ]]
+is_url_handled_rewrited() {
+    local url="$1"
+    # Try to get the url with curl, and keep the http code and an eventual redirection url.
+    local curl_output="$(curl --insecure --silent --output /dev/null \
+      --write-out '%{http_code};%{redirect_url}' "$url")"
+
+    # Cut the output and keep only the first part to keep the http code
+    local http_code="${curl_output%%;*}"
+    # Do the same thing but keep the second part, the redirection url
+    local redirection="${curl_output#*;}"
+
+    # Return 1 if the url isn't handled.
+    # Return 1 if the url has returned 404
+    if [ "$http_code" = "404" ]; then
+        return 1
+    # Return 1 if the url is redirected to the SSO
+    elif [[ $redirection =~ "/yunohost/sso" ]]; then
+        return 1
+    fi
 }
 
 is_url_handled_rewrited() {
diff --git a/scripts/install b/scripts/install
index 2ac648a..e73b3b1 100644
--- a/scripts/install
+++ b/scripts/install
@@ -30,6 +30,21 @@ app=$YNH_APP_INSTANCE_NAME
 # CHECK IF THE APP CAN BE INSTALLED WITH THESE ARGS
 #=================================================
 
+# Stop installation if another app serves "https://${domain}/.well-known/caldav"
+## Waiting for Yunohost to handles this kind of conflict
+## See https://github.com/YunoHost-Apps/baikal_ynh/issues/17
+error_text="Baikal cannot be installed because of a conflit with another application, Nextcloud usually. This app handles the location where you want to install Baikal (https://${domain}/.well-known/caldav). You can either install Baikal on another domain, subdomain or move Nextcloud to another location"
+
+if is_url_handled_rewrited "https://${domain}/.well-known/caldav"; then
+    ynh_die "$error_text"
+fi
+
+# Same test for path "/.well-known/carddav"
+if is_url_handled_rewrited "https://${domain}/.well-known/carddav"; then
+    ynh_die "$error_text"
+fi
+
+
 # Normalize the url path syntax
 path_url=$(ynh_normalize_url_path $path_url)
 
@@ -70,22 +85,6 @@ ynh_setup_source "$final_path"
 # NGINX CONFIGURATION
 #=================================================
 
-# Exits if another app serves "https://${domain}/.well-known/caldav" and display an error message for user
-# Waiting for Yunohost to handles this kind of conflict https://github.com/YunoHost-Apps/baikal_ynh/issues/17
-echo "je suis devant le if"
-if is_url_handled_custom "https://${domain}/.well-known/caldav" ; then
-    echo "je passe dans le if"
-    ynh_die "Baikal cannot be installed because of a conflit with another application, Nextcloud usually. This app handles the location where you want to install Baikal (https://${domain}/.well-known/caldav). You can either install Baikal on another domain, subdomain or move Nextcloud to another location"
-fi
-
-# Taken from https://github.com/YunoHost-Apps/nextcloud_ynh/blob/962cc61ec8ffb045d89dd460cf8b55778d862ffc/scripts/install
-# Commented for now
-#
-# Handle root path, avoid double slash.
-# Temporary fix, in waiting for an upgrade of the helper. (#361)
-#path_url_slash_less=${path_url%/}
-#ynh_replace_string "__PATH__/" "$path_url_slash_less/" "../conf/nginx.conf"
-
 # Create a dedicated nginx config
 ynh_add_nginx_config
 
diff --git a/scripts/upgrade b/scripts/upgrade
index 71d5a9f..9a9d541 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -64,19 +64,33 @@ ynh_setup_source "$final_path"
 # NGINX CONFIGURATION
 #=================================================
 
+ynh_backup_if_checksum_is_different "/etc/nginx/conf.d/$domain.d/$app.conf"
+
 # Delete current nginx configuration to be able to check if .well-known is already served.
 ynh_remove_nginx_config
 ynh_app_setting_delete $app "checksum__etc_nginx_conf.d_$domain.d_$app.conf" || true
+
+
 # Do not serve .well-known if it's already served on the domain
-if is_url_handled "https://${domain}/.well-known/caldav" ; then
-    sed -ri '/^location = \/\.well\-known\/(caldav|carddav) \{/,/\}/d' \
-	"../conf/nginx.conf"
+#if is_url_handled_rewrited "https://${domain}/.well-known/caldav" ; then
+#    sed -ri '/^location = \/\.well\-known\/(caldav|carddav) \{/,/\}/d' \
+#	"../conf/nginx.conf"
+#fi
+
+# Stop installation if another app serves "https://${domain}/.well-known/caldav"
+## Waiting for Yunohost to handles this kind of conflict
+## See https://github.com/YunoHost-Apps/baikal_ynh/issues/17
+error_text="Baikal cannot be installed because of a conflit with another application, Nextcloud usually. This app handles the location where you want to install Baikal (https://${domain}/.well-known/caldav). You can either install Baikal on another domain, subdomain or move Nextcloud to another location"
+
+if is_url_handled_rewrited "https://${domain}/.well-known/caldav"; then
+    ynh_die "$error_text"
+fi
+
+# Same test for path "/.well-known/carddav"
+if is_url_handled_rewrited "https://${domain}/.well-known/carddav"; then
+    ynh_die "$error_text"
 fi
 
-# Handle root path, avoid double slash.
-# Temporary fix, in waiting for an upgrade of the helper. (#361)
-#path_url_slash_less=${path_url%/}
-#ynh_replace_string "__PATH__/" "$path_url_slash_less/" "../conf/nginx.conf"
 
 # Create a dedicated nginx config
 ynh_add_nginx_config