diff --git a/constant_inc.php b/constant_inc.php
index 184dc607b3..d67b282847 100644
--- a/constant_inc.php
+++ b/constant_inc.php
@@ -9,18 +9,6 @@
 	# CONFIGURATION VARIABLES
 	###########################################################################
 
-	########################
-	# PHP Constants
-	########################
-
-	# Directory separator was introduced in PHP 4.0.6
-	if ( !defined( 'DIRECTORY_SEPARATOR' ) ) {
-		if (substr(php_uname(), 0, 7) == 'Windows') {
-			define('DIRECTORY_SEPARATOR', '\\');
-		} else {
-			define('DIRECTORY_SEPARATOR', '/');
-		}
-	}
 
 	########################
 	# Mantis Constants
diff --git a/core_API.php b/core_API.php
index 1d303d4829..0612133e23 100644
--- a/core_API.php
+++ b/core_API.php
@@ -9,6 +9,13 @@
 	# INCLUDES
 	###########################################################################
 
+	# Before doing anything else, start output buffering so we don't prevent
+	#  headers from being sent if there's a blank line in an included file
+	ob_start();
+
+	# Include compatibility file before anything else
+	include( 'core_php_API.php' );
+
   	require( 'constant_inc.php' );
 	if ( file_exists( 'custom_constant_inc.php' ) ) {
 		include( 'custom_constant_inc.php' );
@@ -40,40 +47,6 @@ function obsolete_config_variable($var, $replace) {
 	obsolete_config_variable('g_notify_on_new_threshold', 'g_notify_flags');
 	obsolete_config_variable('g_notify_admin_on_new', 'g_notify_flags');
 
-	ini_set('magic_quotes_runtime', 0);
-
-	# @@@ Experimental
-	# deal with register_globals being Off
-	$t_phpversion = explode('.', phpversion());
-	if ( OFF == $g_register_globals ) {
-		if ( $t_phpversion[0] == 4 && $t_phpversion[1] >= 1 ) {
-			extract( $_REQUEST );
-			extract( $_SERVER );
-		} else {
-			extract( $HTTP_POST_VARS );
-			extract( $HTTP_GET_VARS );
-			extract( $HTTP_SERVER_VARS );
-		}
-	}
-	
-	# Experimental support for $_* variables in PHP < 4.1.0
-	if ( $t_phpversion[0] < 4 || $t_phpversion[1] < 1 ) {
-		global $_REQUEST, $_GET, $_POST, $_COOKIE, $_SERVER;
-		
-		$_GET = $HTTP_GET_VARS;
-		$_POST = $HTTP_POST_VARS;
-		$_COOKIE = $HTTP_COOKIE_VARS;
-		$_SERVER = $HTTP_SERVER_VARS;
-		
-		$_REQUEST = $HTTP_COOKIE_VARS;
-		foreach ($HTTP_POST_VARS as $key => $value) {
-			$_REQUEST[$key] = $value;
-		}
-		foreach ($HTTP_GET_VARS as $key => $value) {
-			$_REQUEST[$key] = $value;
-		}
-	}
-
 	include( 'core_timer_API.php' );
 
 	# initialize our timer
diff --git a/core_php_API.php b/core_php_API.php
new file mode 100644
index 0000000000..4cac3a31ed
--- /dev/null
+++ b/core_php_API.php
@@ -0,0 +1,91 @@
+<?php
+	# Mantis - a php based bugtracking system
+	# Copyright (C) 2000 - 2002  Kenzaburo Ito - kenito@300baud.org
+	# Copyright (C) 2002         Mantis Team   - mantisbt-dev@lists.sourceforge.net
+	# This program is distributed under the terms and conditions of the GPL
+	# See the files README and LICENSE for details
+
+	###########################################################################
+	# PHP Compatibility API
+	#
+	# Methods to help in backwards compatibility of PHP versions, etc.
+	#
+	###########################################################################
+
+	# --------------------
+	# Returns true if the current PHP version is higher than the one
+	#  specified in the given string
+	function php_version_at_least( $p_version_string ) {
+		$t_curver = array_pad( explode( '.', phpversion() ), 3, 0 );
+		$t_minver = array_pad( explode( '.', $p_version_string ), 3, 0 );
+
+		for ($i = 0 ; $i < 3 ; $i = $i + 1 ) {
+			if ( (int)$t_curver[$i] < (int)$t_minver[$i] ) {
+				return false;
+			} else if ( (int)$t_curver[$i] > (int)$t_minver[$i] ) {
+				return true;
+			}
+		}
+
+		# if we get here, the versions must match exactly so:
+		return true; 
+	}
+	# --------------------
+
+	# Enforce our minimum requirements
+	if ( ! php_version_at_least( '4.2.2' ) ) {
+		echo "<b>Your version of PHP is too old.  Mantis requires PHP version 4.0.3 or newer to operate</b>";
+		ob_flush();
+		die();
+	}
+
+	ini_set('magic_quotes_runtime', 0);
+
+	# @@@ Experimental
+	# deal with register_globals being Off
+	# @@@ NOTE we want to get rid of this once we start getting all
+	#      our GPC variables with functions.  In fact we may want to
+	#      turn off register_global_variables if we can
+	if ( OFF == $g_register_globals ) {
+		if ( php_version_at_least( '4.1.0' ) ) {
+			extract( $_REQUEST );
+			extract( $_SERVER );
+		} else {
+			extract( $HTTP_POST_VARS );
+			extract( $HTTP_GET_VARS );
+			extract( $HTTP_SERVER_VARS );
+		}
+	}
+	
+	# Experimental support for $_* auto-global variables in PHP < 4.1.0
+	if ( ! php_version_at_least( '4.1.0' ) ) {
+		global $_REQUEST, $_GET, $_POST, $_COOKIE, $_SERVER;
+		
+		$_GET = $HTTP_GET_VARS;
+		$_POST = $HTTP_POST_VARS;
+		$_COOKIE = $HTTP_COOKIE_VARS;
+		$_SERVER = $HTTP_SERVER_VARS;
+		
+		$_REQUEST = $HTTP_COOKIE_VARS;
+		foreach ($HTTP_POST_VARS as $key => $value) {
+			$_REQUEST[$key] = $value;
+		}
+		foreach ($HTTP_GET_VARS as $key => $value) {
+			$_REQUEST[$key] = $value;
+		}
+	}
+
+	########################
+	# PHP Constants
+	########################
+
+	# Directory separator was introduced in PHP 4.0.6
+	if ( !defined( 'DIRECTORY_SEPARATOR' ) ) {
+		if (substr(php_uname(), 0, 7) == 'Windows') {
+			define('DIRECTORY_SEPARATOR', '\\');
+		} else {
+			define('DIRECTORY_SEPARATOR', '/');
+		}
+	}
+
+?>
diff --git a/core_security_API.php b/core_security_API.php
index 0c9ec22c40..fd652ff22c 100644
--- a/core_security_API.php
+++ b/core_security_API.php
@@ -6,11 +6,11 @@
 	# See the files README and LICENSE for details
 
 	# --------------------------------------------------------
-	# $Revision: 1.2 $
-	# $Author: jlatour $
-	# $Date: 2002-08-22 18:15:10 $
+	# $Revision: 1.3 $
+	# $Author: jfitzell $
+	# $Date: 2002-08-23 01:34:08 $
 	#
-	# $Id: core_security_API.php,v 1.2 2002-08-22 18:15:10 jlatour Exp $
+	# $Id: core_security_API.php,v 1.3 2002-08-23 01:34:08 jfitzell Exp $
 	# --------------------------------------------------------
 
 	###########################################################################
@@ -22,7 +22,10 @@
 	# If the variable is not set, the default is returned. 
 	# If magic_quotes_gpc is on, slashes will be stripped from the value before being returned.
 	function get_var( $p_var_name, $p_default = 'nil' ) {
-		global $_REQUEST;
+		# simulate auto-globals from PHP v4.1.0 (see also code in core_php_API.php)
+		if ( ! php_version_at_least( '4.1.0' ) ) {
+			global $_REQUEST;
+		}
 
 		if ( isset( $_REQUEST[$p_var_name] ) ) {
 			$t_result = $_REQUEST[$p_var_name];