Please help with the theme update December 10th, 2015

Hi
Tell me please, I bought the topic in mid-2016. I did my site and it worked fine. By the end of 2016, I froze my project, but a year later I decided to restore it, and I ran into a problem. when I looked in the mail, I saw that the topic came out grandiose update I tried to update since it is written here (http://support.skywarriorthemes.com/?topic=updating-theme-step-by-step) but I have did not work, the entire site skewed half of the posts does not seem to. I’m looking to add a plug-in (Visual Composer). Can you please tell me if I can somehow painlessly update my site from the version (December 10th, 2015) to (Current version: 2.3.1 September 2nd, 2017)