session validation: check for tt-rss version

include/functions.php

@@ -630,6 +630,7 @@
 				@session_start();
 
 				$_SESSION["uid"] = $user_id;
+				$_SESSION["version"] = VERSION;
 
 				$result = db_query($link, "SELECT login,access_level,pwd_hash FROM ttrss_users
 					WHERE id = '$user_id'");

include/sessions.php

@@ -5,6 +5,7 @@
 	require_once "db.php";
 	require_once "lib/accept-to-gettext.php";
 	require_once "lib/gettext/gettext.inc";
+	require_once "version.php";
 
 	$session_expire = max(SESSION_COOKIE_LIFETIME, 86400);
 	$session_name = (!defined('TTRSS_SESSION_NAME')) ? "ttrss_sid" : TTRSS_SESSION_NAME;
@@ -38,6 +39,8 @@
 		if (SINGLE_USER_MODE) return true;
 		if (!$link) return false;
 
+		if (VERSION != $_SESSION["version"]) return false;
+
 		$check_ip = $_SESSION['ip_address'];
 
 		switch (SESSION_CHECK_ADDRESS) {