Finally decided to upgrade my forum (http://tf-russia.ru/forum/) to PHPBB 3.1, because my hoster recently upgraded software. I followed the instructions here https://www.phpbb.com/support/docs/en/3 ... /upgrade3/ then checked rights for folders /install, /cache, /files, /store and changed them to 777. Rights for config.php is 666. Now when I open http://tf-russia.ru/forum/install/database_update.php I get white screen or message that server or file isn't found
