Updated UPGRADING to add three changes

UPGRADING

@@ -183,6 +183,18 @@ PHP 5.6 UPGRADE NOTES
   CURLOPT_SAFE_UPLOAD is now turned on by default and uploads with @file 
   do not work unless it is explicitly set to false.
 
+  curl_setopt() now supports the following nullable settings (>= 5.5.11): 
+    . CURLOPT_CUSTOMREQUEST
+    . CURLOPT_FTPPORT
+    . CURLOPT_RANGE
+    . CURLOPT_FTP_ACCOUNT
+    . CURLOPT_RTSP_SESSION_ID
+    . CURLOPT_KRBLEVEL
+    . CURLOPT_KRB4LEVEL
+
+- Strings:
+  substr_compare() now allows $length to be zero.
+
 - Crypt:
   crypt() will now raise an E_NOTICE error if the salt parameter is omitted.
   See: https://wiki.php.net/rfc/crypt_function_salt
@@ -240,6 +252,9 @@ PHP 5.6 UPGRADE NOTES
 - Zip:
   Added ZipArchive::setPassword($password)
 
+- SPL
+  Added SplFileObject::fread($length) to complement fwrite() method (>= 5.5.11)
+
 ========================================
 6. New Classes and Interfaces
 ========================================