No, because the config is stored on disk. This means that if you installed an old client and it wrote '1' to disk, no matter how often you upgrade, it always uses version 1. This should not be a config setting, it's a client property.(new clients should prefer the most recent client version).

The actual protocol used is the highest protocol that both client and server support. (2 if both clent and server are new, 1 if one of the two is old).