There are couple points that need to be remembered at the time of upgrading the plugin, first of take backup of your Logo and icons folders, the plugin doesn't remove the database records ( Stores and Categories) so you don't need to worry about that. You have to make backup of Logo and icons folder which are located at these paths.
Once you download the above folders, delete the plugin from wordpress backend Plugins Installed Plugins
Once you delete the plugin install the new release, reupload your logo and icon folders on the same directory from where you have downloaded it, so your logos and icons wouldn't be missing from the store locator. If you have any problem email us at [email protected].
Upgradation for Version Above 4.3.x
For version above 4.3.x, you can simply download all your assets from the Dashboard Backup Assets button and upload it in the newly uploaded version.