  We revisit the procedure of deformation of $C^*$-algebras via coactions of
locally compact groups and extend the methods to cover deformations for
maximal, reduced, and exotic coactions for a given group $G$ and circle-valued
Borel $2$-cocycles on $G$. In the special case of reduced (or normal) coactions
our deformation method substantially differs from -- but turns out to be
equivalent to -- the ones used by previous authors, specially those given by
Bhowmick, Neshveyev, and Sangha in [7].
  Our approach yields all expected results, like a good behaviour of
deformations under nuclearity, continuity of fields of $C^*$-algebras and
$K$-theory invariance under mild conditions.
