diff --git a/README.rst b/README.rst
index 0fc8ff0..2a36751 100644
--- a/README.rst
+++ b/README.rst
@@ -63,7 +63,7 @@ This project also provides a webservice to generate a Factur-X invoice from a re
 * **attachment2** -> Second attachment (optional)
 * ...
 
-It is recommended to run the webservice behind an HTTPS/HTTP proxy such as `Nginx <https://www.nginx.com/>`_ or `Apache <https://httpd.apache.org/>`_.
+It is recommended to run the webservice behind an HTTPS/HTTP proxy such as `Nginx <https://www.nginx.com/>`_ or `Apache <https://httpd.apache.org/>`_. You will certainly have to increase the default maximum upload size (default value is only 1MB under Nginx!): use the parameter **client_max_body_size** for Nginx and **LimitRequestBody** for Apache.
 
 You can use `curl <https://curl.haxx.se/>`_, a command line tool to send HTTP requests (on Linux Ubuntu/Debian, just install the **curl** package) to generate the request: