Best practices for handling API (not ABI) breaks?

[Daniel Burrows <dburrows@debian.org>]

  Hi,

  I'm the maintainer of libsigc++-2.0, a typesafe callback library for
C++.  Upstream has just released a new version, 2.2, which preserves the
version 2.0 ABI but is not source-compatible: programs that compiled
against the 2.0 series will break with this new release.  There are 114
packages that depend on libsigc++-0, too many to do this just by bugging
a few maintainers to recompile.

  What's the best practice for handling this situation?

    Thanks,
  Daniel