Hi,
To update it's quite simple, you have to download the latest package from our website, actually the 2.3.0.
Then thanks to the Joomla extension manager install the latest package, it will be installed over the old one.
Don't worry, you will not lose any settings. And if somes vies have been edited thanks to the views override (Display > Views menu in HikaShop) you will not lose the changes.
Sometimes it can happen some errors depending on the configuration, or anything else.
The best way to update safely is just to duplicate the website in order to have a test environment and a production one.