  In relation to the newly observed bottom-strange X^{+,-}(5568) mesons, we
revisit our tetra-quark interpretation of X(3872) and Z_c(3900). It is
discussed that our assignment of X^{+,-}(5568) to charged components of
iso-triplet bottom partners of D_{s0}^+(2317) is compatible with the revised
version of our tetra-quark interpretation of X(3872) and Z_c(3900).
