  Earlier we presented a method to decompose modal formulas for processes with
the internal action $\tau$, and congruence formats for branching and
$\eta$-bisimilarity were derived on the basis of this decomposition method. The
idea is that a congruence format for a semantics must ensure that the formulas
in the modal characterisation of this semantics are always decomposed into
formulas that are again in this modal characterisation. In this follow-up paper
the decomposition method is enhanced to deal with modal characterisations that
contain a modality $\langle\epsilon\rangle\langle a\rangle\phi$, to derive
congruence formats for delay and weak bisimilarity.
