i got a blank page when upgrading from 1.5.6.3 to 2.0

Hi All

I got failed when upgrading OpenCart from 1.5.6.3 to 2.0, the following steps are what i have done:

1. download and upload opencart 2.0 to my web server by FTP (overwrite all the older files)
2. type http://mystore.com/install in the chrome browser
3. i have got the upgrade instruction page correctly.
4. i press 「Continue」 button
5. then i just got a blank page, nothing running...

please can somebody advice which steps i have missed or incorrect? please help! thank you so much.

Upgrade to 2.0 is advisable.

Wait until we release a working upgrade-script.