I have 2 similar (say linux) platforms A and B. A supports C++03 and C++11; however B supports only C++03 compiler.
I compile code (with C++03) on platform A and able to run its binary on B without any problem. Is this case true for C++11 also ? (It may work in my platform, but want to know in broader sense).
In other words, is C++11 limited till compilation only or it's also a framework enhancement (added with support for new libraries and threads)?
In general, yes, but there should be C++0X runtime libraries present on the target machine, or you should have the runtime statically linked into the executable.
Once you have binaries or executable's they should work on any platform. That is the purpose of them in the first place.
Since C++, whatever version, compiles down to Assembly (and OS-API-calls if dynamically linked), sure can do, as long as the instruction set is supported by the platform (and the proper DLLs are present).
To contrast the Linux-specific answer:
Windows does not have the notion of "supported C++ platforms". It works the other way around: C++ compilers can target different Windows versions. The C++ runtime for VS2010 supports XP SP2 and later.