For any new projects or long-term support, Siemens recommends migrating to (Basic, Comfort, or Advanced Runtime), which is the established successor system. You can check the compatibility of your current operating system with these versions using the official Siemens Compatibility Tool. Service Pack 5 for SIMATIC WinCC flexible 2008 - Support
If WinCC Flexible 2008 SP6 is not available for free or you prefer a more current solution, consider looking into newer versions of Siemens' HMI configuration software or exploring offerings from other companies in the industrial automation sector. Some of these might offer free trials, demo versions, or even community-supported versions. wincc flexible 2008 sp6 free
SP6 added support for Windows 8.1 and fixed a critical bug related to recipe data loss. It is the recommended version for anyone stuck on WinCC Flexible. For any new projects or long-term support, Siemens