In reply to Diana.

Diana, WordPress versions are maintained for security fixes for two or three years. The last secure version of WordPress is 3.7.13. I don't recommend that anyone go that far back as 3.7 will be dropped any day soon, but any version from 4.0 on still has at least a year of life in it.

To apply this information to your particular case, you should downgrade and stay on the 4.4 release until Visual Composer is updated to work with 4.5. Personally I wouldn't build a site with Visual Composer but that's an entirely different question.

Good luck!