We will periodically provide updates of This Theme. These updates are essential if you want to have a bug-free website as we give new features and improvements to the theme over time. Some of these updates might be needed in order to make the theme compatible with newer versions of WordPress and Third Party included plugins.
here are three ways of updating our WordPress themes to newer versions:
The easiest way of updating the theme is via Dashboard > Updates. When an update is available for your theme, you will get a notification in your WordPress Dashboard and you can update your theme by clicking on Dashboard > Updates and updating the theme (just as you would update any other installed theme).
Another way of updating your theme is via FTP. Extract the contents of the theoutset.zip file (which you will find inside the theme update file you have downloaded from Themeforest). The contents will be extracted to a folder called Theoutset\ and to subfolders within the theoutset folder.
Using an FTP program, upload theoutset\ folder (and its subfolders) to /wp-content/themes/ on your web server.
Final Tip: Whichever method you use to update your theme, clear your browser cache after each update if you notice anything off. Old theme files can sometimes persist in your local cache and make you think something’s wrong.
Advance reference Link: How to update theme without losing customisation – Read More