Equivariant quadratic forms in characteristic 2

Let $G$ be a finite group and $K$ a finite field of characteristic $2$. Denote by $t$ the $2$-rank of the commutator factor group $G\mathrm{/}{G}^{\mathrm{\prime }}$ and by $s$ the number of self-dual simple $KG$-modules. Then the Witt group of equivariant quadratic forms $\text{WQ}(K,G)$ is isomorphic to an elementary abelian $2$-group of rank $s+t$.