To know more on system requirements, please refer this article:
We are no longer making any updates to RealPlayer Cloud, RealPlayer 16, or prior versions, so some features (such as Download This Video) may not work on these versions.
As RealNetworks makes new products available to customers, it's not possible for us to continue supporting older products.
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).