To update the component you don't need any particular operations.

Once downloaded the latest release from your reserved area, you need simply to upload and install the package using the Joomla Extensions Manager as usual. During the installation the extension will be updated and files overwritten automatically. After that, when you access the control panel of JSitemap you will be prompted with a green label informing you that the latest version is installed.

After having updated the component, no settings or configuration will be lost. Only the files and database tables used by the component will be updated, but all settings and data sources will be preserved.
REMEMBER TO CLEAR THE BROWSER CACHE AFTER UPDATES TO REFRESH SCRIPTS AND STYLES.
In some cases you may need to clear the Joomla! cache too and logout/login in the backend again.

Although to update the component it's only required to download and install the latest package using the Joomla installer, as long as you have a valid ongoing updates license you may choose to take advantage of the Auto Updater included in the component or the standard Joomla! Updater.

Starting from the version 3.7 of JSitemap an Auto Updater is included in the component. As you may know when you purchase JSitemap Professional, free updates are included for 1 year from the date of the latest valid purchase. As long as you have a valid ongoing updates license you may choose to take advantage of the Auto Updater included in the component.

Both the component Auto Updater and the Joomla! Updater require you to specify exactly your email address used to register your account and perform the purchase on our store http://storejextensions.org to check the validity status of your updates license and automatically prompt you to download and install updates as soon as they are available.
Pay attention that if you are using the Joomla! auto updater the plugin 'System - JSitemap utilities', that is required for the license validation, must be published and active otherwise you won't be able to auto update the component receiving an error 'The XML file did not contain an administrative element'.

Notice that the standard Joomla! Updater will work in the same way of the built-in component updater once you specified a valid email address for the updates license validation, but this is available starting from version 4.2 of JSitemap.