I would recommend that you restore your DB and site from backup to 1.10.4.
1.11-rc1 is not for production use. It is a Release Candidate with a lot of fixes for it over on git hub.
A blank white screen means that there is a PHP error, you would have to consult your PHP error logs to see what the issue is.
Also please help us to help you by reading and following the posting guidelines located in this thread: Please read before requesting assistance. The more information you give us the better we will be able to assist you. Thank you.