As RealNetworks makes new products available to customers, it is not possible to continue supporting legacy and historic products, including: RealPlayer 15, 14, SP and 11 (for Windows), 10.5 and 10 (Windows and Mac)
To know more on this, please refer to this article: https://customer.real.com/hc/en-us/articles/204039423
After re-evaluating market trends, we have decided not to make RealPlayer/RealTimes available on Windows XP or Vista.
We always recommend using our most current version, which you can download from www.real.com. The most current version is RealPlayer with RealTimes, available for customers on Windows 7 and higher (or Mac OS X 10.10 and higher).