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PayPal HTTP 1.1 Specifications

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  • PayPal HTTP 1.1 Specifications

    Just been asked about this by a client using v10 - does any one understand it and do we need to be doing anything?


    Dear (Mrs Actinic User),

    In a bulletin dated the 18th of October, 2011, we announced that we were going to expand the number of IP addresses for to improve our site’s performance, scalability and availability. As part of this transition, we planned to discontinue support for HTTP 1.0 protocol starting the 7th of October, 2013.

    We have recently identified that this change may impact the ability of some of our merchants to perform IPN (Instant Payment Notification) post-back validation or PDT (Payment Data Transfer) posts to and This happens when the IPN or PDT scripts use HTTP 1.0 protocol and do not include the “Host:” or “Host:” header in the HTTP request.

    Additional Details

    Starting the 7th of October, 2013, we will require all incoming requests to have a “Host” header which complies with HTTP 1.1 Specifications. This header was not required under HTTP 1.0. IPN and PDT scripts using HTTP 1.0 may start failing with “HTTP/1.0 400 Bad Request” errors after the 7th of October, 2013, which will result in IPN messages not being validated successfully, or PDT scripts not being able to retrieve transaction information.

    Action Required before the 7th of October, 2013

    Merchants need to update their IPN and/or PDT scripts to use HTTP 1.1, and include the “Host” and “Connection: close” HTTP header in the IPN postback script.

    Example with Host as (please make necessary changes if you are using

    //Set values for the request back

    $req=HTTP::Request->new('POST', '');
    $req->header(Host=> '');
    $req->header(Connection=> 'close');
    // post back to PayPal system to validate
    $header="POST /cgi-bin/webscr HTTP/1.1\r\n";
    $header .="Content-Type: application/x-www-form-urlencoded\r\n";
    $header .="Host:\r\n";
    $header .="Connection: close\r\n\r\n";

    HttpsURLConnection uc=(HttpsURLConnection) u.openConnection();
    uc.setRequestProperty("Host", "");
    uc.setRequestProperty("Connection", "Close");

    The PayPal Sandbox has been configured to reject any HTTP requests without the “Host” header with HTTP 400 error. Merchants can use the Sandbox environment to certify the changes to their IPN and PDT scripts.

    For more information on PDT and IPN, please refer to and For additional information or questions about this change, please contact PayPal's Merchant Technical Support team via


    Thank you
    Jonathan Chappell
    Website Designer
    SellerDeck Website Designer
    Actinic to SellerDeck upgrades
    Graphicz Limited -

  • #2
    See here:


    • #3
      Thanks Duncan - that'll teach me to read the stickies!!!
      Jonathan Chappell
      Website Designer
      SellerDeck Website Designer
      Actinic to SellerDeck upgrades
      Graphicz Limited -


      • #4
        Paypal stopped working - tried that but with no success


        I tried the fix but to no avail
        A test Paypal purchase is showing the following error message

        502 - Web server received an invalid response while acting as a gateway or proxy server.

        There is a problem with the page you are looking for, and it cannot be displayed. When the Web server (while acting as a gateway or proxy) contacted the upstream content server, it received an invalid response from the content server.

        Are you able to help?




        • #5
          Possibly all that is needed is to substitute from V11 to V10 to make it work. Can anyone post a copy of here and I am happy to test it.


          • #6
            You can download previous versions of Sellerdeck from the archive here

            First Tackle - Fly Fishing and Game Angling