Earlier this year, it was announced that Jolla and Sony are entering into a partnership to bring Sailfish OS to Xperia devices (starting with the Xperia X single SIM version). In August, Jolla revealed that Sailfish X - Sailfish OS for the Xperia X - will be paid, and available around the end of September. Although a bit late, the new OS is now available to purchase and download. As of today, you will be able to purchase Sailfish X, and install it on your Sony Xperia X. Installation instructions are currently only available for Windows users, with the company saying that...
Source: https://www.gsmarena.com/sailfish_x_sailfish_os_for_sony_xperia_x_is_now_available_to_purchase_and_download-news-27675.php