Why does the program who has a embeded manifest with CRT version 30729.4148 runs with 30729.6161(latest) in winsxs folder on runtime?

I have a question really really wondering.

I installed various versions of visual studio 2008 redistribution package in my machine. Now, 30729.6161 is up to date.

In this environment, I made a simple program with embeded manifest which only refer to 30729.4148 CRT runtime library开发者_运维技巧.

But, when I ran the program, this has loaded not a 30729.4148 version of CRT library but 30729.6161.

Why does this work?

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The new runtime comes with policy files that redirects clients with older versions to the newer version.

See:

%WinDir%\WinSxS\Policies