Let M be a 4‐manifold with residually finite fundamental group G having b1(G) > 0. Assume that M carries a symplectic structure with trivial canonical class K=0∈H2(M). Using a theorem of Bauer and Li, together with some classical results in 4‐manifold topology, we show that for a large class of groups M is determined up to homotopy and, in favorable circumstances, up to homeomorphism by its fundamental group. This is analogous to what was proved by Morgan–Szabó in the case of b1=0 and provides further evidence to the conjectural classification of symplectic 4‐manifolds with K=0. As a side, we obtain a result that has some independent interest, namely the fact that the fundamental group of a surface bundle over a surface is large, except for the obvious cases.