  We establish universal behavior in temperature dependencies of some
observables in $(s+id)$-wave BCS superconductivity in the presence of a weak
$s$ wave. There also could appear a second second-order phase transition. As
temperature is lowered past the usual critical temperature $T_c$, a less
ordered superconducting phase is created in $d$ wave, which changes to a more
ordered phase in $(s+id)$ wave at $T_{c1}$ ($< T_c$). The presence of two phase
transitions manifest in two jumps in specific heat at $T_c$ and $T_{c1}$. The
temperature dependencies of susceptibility, penetration depth, and thermal
conductivity also confirm the new phase transition.
