Updating a theme in WordPress is easy. The process is simply replacing old files with new files.

Update won't change any content of the site, any publication or page ar even a setting. It just replaces some files.

Manual FTP method

You can connect to your host using FTP and navigate to wp-content/themes directory. Delete the hubble folder and upload the new one. Now you have updated your theme.

Next step is to login to admin panel Appearance > About Hubble Theme and see if you need to update the Hubble Theme Plugin.

Using Admin Panel Only

Go to your admin panel Appearance > Themes.

Activate another theme than Hubble.

Click on Hubble theme thumbnail to open a popup window and delete the Hubble Theme.

Then upload the new theme version and activate it.

Now you have updated your theme.

Next step is to login to admin panel Appearance > About Hubble Theme and see if you need to update the Hubble Theme Plugin.

Benefit Automatic Update

You can install and activate the Envato Market Plugin. Then you can go to the plugin page from the main menu at admin panel and configure it with your Envato account ( the account that you have bought the theme ) and you will be notified about updates as soon as they are published, then you can one click update your theme like free themes.

Next step is to login to admin panel Appearance > About Hubble Theme and see if you need to update the Hubble Theme Plugin.