Update from version 4 to 8

I have an old website on Osclass Evolution v. 4.4. How do I upgrade it to version 8.4? And will there be any problems?
In Osclass 4, the admin panel says that no update is required.
How do I make an update?

First you should take backup of files and database.
Next, you should be able to update, if you manually replace all files (download zip and extract it on your server).

First you should take backup of files and database.
Next, you should be able to update, if you manually replace all files (download zip and extract it on your server).

Thank you, I’ll give it a try.