A Windows program built with Visual C++ that uses the redistributable library is tied to that specific version of the library. They are not ABI compatible with each other.

So, if you have one program that uses the 32-bit 2008 redistributable, and another program that uses the 32-bit 2015 redistributable, and a third that uses the 64-bit 2015 redistributable, you need to have all three versions installed.

Note that Windows Update will provide security and critical updates for these runtimes, so after installing one, you should check for and install its updates as soon as possible.