To update your extension to the latest version, you only need to login your Magestore account => go to My Downloadable Products and download the latest or most suitable package with your Magento version. Then install the package following our detailed installation guide: Magento 1 & Magento 2
Please notice that all of your customization implemented in your current version will be lost after updating. Thus, please check carefully again with your coordinates before doing it. Besides, don’t forget to back-up your data and package to avoid unexpected events.
In particular, with Paid Customization which was made by Magestore before in your site, you can refer the full Term and Condition of Customization Service for more details