qiskit/releasenotes/notes/0.22/remove-pulse-defs-old-20q-4...

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---
upgrade:
- |
The fake backend objects :class:`~.FakeJohannesburg`,
:class:`~.FakeJohannesburgV2`, :class:`~.FakeAlmaden`,
:class:`~.FakeAlmadenV2`, :class:`~.FakeSingapore`, and
:class:`~.FakeSingaporeV2` no longer contain the pulse defaults payloads.
This means for the :class:`~.BackendV1` based classes the
:meth:`.BackendV1.defaults` method and pulse simulation via
:meth:`.BackendV1.run` is no longer available. For :class:`~.BackendV2`
based classes the :attr:`~InstructionProperties.calibration` property for
instructions in the :class:`~.Target` is no longer populated. This
change was done because these systems had exceedingly large pulse defaults
payloads (in total ~50MB) due to using sampled waveforms instead of
parameteric pulse definitions. These three payload files took > 50% of the
disk space required to install qiskit-terra. When weighed against the
potential value of being able to compile with pulse awareness or pulse
simulate these retired devices the file size is not worth the cost. If
you require to leverage these properties you can leverage an older version
of Qiskit and leverage :mod:`~qiskit.qpy` to transfer circuits from
older versions of qiskit into the current release.