Thanks for providing us further details.
Well, I think your older version v4.7.1 might work on Windows Server 2012 R2 although I am not entirely certain about it. Please check if you could find .NET framework 2.0 compiled version of the component at your installation directory (in e.g net2.0 folder), you may try this version on your Windows Server 2012 R2, it might work fine on it. If you do not have .NET framework 2.0 compiled version of the component, I am afraid, you might not use Aspose.Cells on the underlying server.
Moreover, we highly recommend you to kindly try and upgrade to our latest version/fix (e.g v8.6.0 (latest version)). Over the years, we have made lots of enhancements, included new features and included lots of fixes in the newer versions of the product. The latest versions of the product do work well on both 32 bits and 64-bits system, you may read, write, manipulate, render or print Advanced MS Excel (2007/2010, 2013) file formats (e.g XLS, XLSX, XLSM, XLSB etc.).