Currently there is no way to determine by inspection of the version.h header what version of the C++ driver is being used if only the headers and library are available. The only way to do so it is to compile a test file and link it against the library.

It would be good to have a version identifier in the header that can be extracted without needing to compile the header or link against the client library (like with grep). This would make it trivial to write a FindMongoClient analogue of FindBoost in CMake, for instance.