Documentation: Update required redistributable version

docs/Installing.md

@@ -10,8 +10,9 @@ This pre-built version comes pre-built wit Lua support. Libraries for SSL suppor
 however, users may add an SSL library themselves.
 Instructions for adding SSL support can be found in [https://github.com/civetweb/civetweb/tree/master/docs](https://github.com/civetweb/civetweb/tree/master/docs)
 
-1a. 32 Bit: Install the [Visual C++ Redistributable for Visual Studio 2010](http://www.microsoft.com/en-us/download/details.aspx?id=8328)
-1b. 64 Bit: Install the [Visual C++ Redistributable for Visual Studio 2013](http://www.microsoft.com/en-us/download/details.aspx?id=40784)
+1. In case the Visual C++ Redistributable are not already installed:
+  32 Bit Version: Install the [Redistributable for Visual Studio 2010](http://www.microsoft.com/en-us/download/details.aspx?id=8328)
+  64 Bit Version: Install the [Redistributable for Visual Studio 2015](http://www.microsoft.com/en-us/download/details.aspx?id=48145)
 2. Download latest *civetweb-win.zip* from [SourceForge](https://sourceforge.net/projects/civetweb/files/)
 3. When started, Civetweb puts itself into the tray.