PlusClient is not available in the updated game services.
from this link
private GoogleApiClient buildGoogleApiClient() {
return new GoogleApiClient.Builder(SigninActivity.this).addConnectionCallbacks(this)
.addOnConnectionFailedListener(this).addApi(Plus.API, Plus.PlusOptions.builder().build())
.addScope(Plus.SCOPE_PLUS_LOGIN).build();
}
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