diff --git a/classes/auth/internal.php b/classes/auth/internal.php
index 37014ce47..92c19eb64 100644
--- a/classes/auth/internal.php
+++ b/classes/auth/internal.php
@@ -9,7 +9,7 @@ class Auth_Internal extends Auth_Base {
 		$otp = db_escape_string($_REQUEST["otp"]);
 
 		if (get_schema_version($this->link) > 96) {
-			if (!defined('AUTH_DISABLE_OTP') || !AUTH_DISABLE_OTP) {
+			if (version_compare(PHP_VERSION, '5.3.0') >= 0 && !defined('AUTH_DISABLE_OTP') || !AUTH_DISABLE_OTP) {
 				$result = db_query($this->link, "SELECT otp_enabled,salt FROM ttrss_users WHERE
 					login = '$login'");
 
diff --git a/classes/pref/prefs.php b/classes/pref/prefs.php
index e9f420774..f4a663dbd 100644
--- a/classes/pref/prefs.php
+++ b/classes/pref/prefs.php
@@ -258,7 +258,7 @@ class Pref_Prefs extends Handler_Protected {
 
 			print "</form>";
 
-			if ($_SESSION["auth_module"] == "internal") {
+			if (version_compare(PHP_VERSION, '5.3.0') >= 0 && $_SESSION["auth_module"] == "internal") {
 
 				print "<h2>" . __("One time passwords / Authenticator") . "</h2>";