diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index bbc11c5f7a..52759950d7 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -3619,7 +3619,7 @@ function iis7_supports_permalinks() {
 		 * Lastly we make sure that PHP is running via FastCGI. This is important because if it runs
 		 * via ISAPI then pretty permalinks will not work.
 		 */
-		$supports_permalinks = class_exists('DOMDocument') && isset($_SERVER['IIS_UrlRewriteModule']) && ( php_sapi_name() == 'cgi-fcgi' );
+		$supports_permalinks = class_exists('DOMDocument') && isset($_SERVER['IIS_UrlRewriteModule']) && ( PHP_SAPI == 'cgi-fcgi' );
 	}
 
 	/**
diff --git a/src/wp-includes/load.php b/src/wp-includes/load.php
index 14f74fc863..99e4b486d6 100644
--- a/src/wp-includes/load.php
+++ b/src/wp-includes/load.php
@@ -52,7 +52,7 @@ function wp_fix_server_vars() {
 	$_SERVER = array_merge( $default_server_values, $_SERVER );
 
 	// Fix for IIS when running with PHP ISAPI
-	if ( empty( $_SERVER['REQUEST_URI'] ) || ( php_sapi_name() != 'cgi-fcgi' && preg_match( '/^Microsoft-IIS\//', $_SERVER['SERVER_SOFTWARE'] ) ) ) {
+	if ( empty( $_SERVER['REQUEST_URI'] ) || ( PHP_SAPI != 'cgi-fcgi' && preg_match( '/^Microsoft-IIS\//', $_SERVER['SERVER_SOFTWARE'] ) ) ) {
 
 		// IIS Mod-Rewrite
 		if ( isset( $_SERVER['HTTP_X_ORIGINAL_URL'] ) ) {
diff --git a/src/wp-includes/pluggable.php b/src/wp-includes/pluggable.php
index a2bac5af3f..0c871388b2 100644
--- a/src/wp-includes/pluggable.php
+++ b/src/wp-includes/pluggable.php
@@ -1172,7 +1172,7 @@ function wp_redirect($location, $status = 302) {
 
 	$location = wp_sanitize_redirect($location);
 
-	if ( !$is_IIS && php_sapi_name() != 'cgi-fcgi' )
+	if ( !$is_IIS && PHP_SAPI != 'cgi-fcgi' )
 		status_header($status); // This causes problems on IIS and some FastCGI setups
 
 	header("Location: $location", true, $status);