Compatibility of CorelDRAW x4 and CorelDRAW x7

Hello! At the enterprise where I job we have a lot of files created with coreldraw x4. The problem is that we have some licenses coreldraw x7, but when the users want open a coreldraw x4 file within of coreldraw x7 shows them a blank page.

It's normal? Isn't compatible both versions?

Thanks in advance.