diff --git a/README.txt b/README.txt
index 474074a..cd456fd 100644
--- a/README.txt
+++ b/README.txt
@@ -27,7 +27,8 @@ limits, chunk size, and max redirects to follow. Can handle data with
 content-encoding and transfer-encoding headers set. Correctly follows
 redirects. Option to forward the referrer when a redirect is found. Cookie
 extraction and parsing into key value pairs. Can multipart encode data so files
-can easily be sent in a HTTP request.
+can easily be sent in a HTTP request. Will emulate a range request if the server
+does not support range requests.
 
 
 REQUIREMENTS
@@ -53,6 +54,10 @@ Settings page is located at:
  * IP Address to send all self server requests to. If left blank it will use the
    same server as the request. If set to -1 it will use the host name instead of
    an IP address. This controls the output of httprl_build_url_self().
+ * Enable background callbacks. If disabled all background_callback keys will
+   be turned into callback & httprl_queue_background_callback will return NULL
+   and not queue up the request. Note that background callbacks will
+   automatically be disabled if the site is in maintenance mode.
 
 
 API OVERVIEW
@@ -71,6 +76,8 @@ httprl_queue_background_callback()
  - Queue a special HTTP request (used for threading) in httprl_send_request().
 
 Other Functions:
+httprl_is_background_callback_capable()
+ - See if httprl can issue a background callback.
 httprl_background_processing()
  - Output text, close connection, continue processing in the background.
 httprl_strlen()
@@ -116,6 +123,21 @@ Request http://drupal.org/.
     ?>
 
 
+Request http://drupal.org/robots.txt and save it to tmp folder.
+
+    <?php
+    // Queue up the request.
+    httprl_request('http://drupal.org/robots.txt');
+    // Execute request.
+    $request = httprl_send_request();
+
+    // Save file if we got a 200 back.
+    if ($request['http://drupal.org/robots.txt']->code == 200) {
+      file_put_contents('/tmp/robots.txt', $request['http://drupal.org/robots.txt']->data);
+    }
+    ?>
+
+
 Request this servers own front page & the node page.
 
     <?php
@@ -432,6 +454,11 @@ Send 2 files in one field via a POST request.
 Use 2 threads to load up 4 different nodes.
 
     <?php
+    // Bail out here if background callbacks are disabled.
+    if (!httprl_is_background_callback_capable()) {
+      return FALSE;
+    }
+
     // List of nodes to load; 241-244.
     $nodes = array(241 => '', 242 => '', 243 => '', 244 => '');
     foreach ($nodes as $nid => &$node) {
@@ -462,6 +489,11 @@ Run a function in the background. Notice that there is no return or printed key
 in the callback options.
 
     <?php
+    // Bail out here if background callbacks are disabled.
+    if (!httprl_is_background_callback_capable()) {
+      return FALSE;
+    }
+
     // Setup callback options array; call watchdog in the background.
     $callback_options = array(
       array(
@@ -488,6 +520,11 @@ D6 & D7.
     // Show first module before running system_get_files_database().
     echo httprl_pr(current($modules));
 
+    // Bail out here if background callbacks are disabled.
+    if (!httprl_is_background_callback_capable()) {
+      return FALSE;
+    }
+
     $callback_options = array(
       array(
         'function' => 'system_get_files_database',
@@ -515,6 +552,11 @@ Get 2 results from 2 different queries at the hook_boot bootstrap level in D6.
     unset($x, $y);
 
 
+    // Bail out here if background callbacks are disabled.
+    if (!httprl_is_background_callback_capable()) {
+      return FALSE;
+    }
+
     // Run above 2 queries and get the result via a background callback.
     $args = array(
       // First query.
@@ -572,6 +614,12 @@ Get 2 results from 2 different queries at the hook_boot bootstrap level in D7.
     echo $x . "<br \>\n" . $y . "<br \>\n";
     unset($x, $y);
 
+
+    // Bail out here if background callbacks are disabled.
+    if (!httprl_is_background_callback_capable()) {
+      return FALSE;
+    }
+
     // Run above 2 queries and get the result via a background callback.
     $args = array(
       // First query.
@@ -661,6 +709,11 @@ non blocking background request.
     system_clear_cache_submit();
 
 
+    // Bail out here if background callbacks are disabled.
+    if (!httprl_is_background_callback_capable()) {
+      return FALSE;
+    }
+
     // How to do it in a non blocking background request.
     $args = array(
       array(