---
upgrade:
  - |
    Updates gate fusion default thresholds so that gate fusion will be applied
    to circuits with of more than 14 qubits for statevector simulations on the
    :class:`~qiskit.providers.aer.StatevectorSimulator` and 
    :class:`~qiskit.providers.aer.QasmSimulator`.
    
    For the ``"density_matrix"``
    method of the :class:`~qiskit.providers.aer.QasmSimulator` and for the
    :class:`~qiskit.providers.aer.UnitarySimulator` gate fusion will be applied
    to circuits with more than 7 qubits.
    
    Custom qubit threshold values can be set using the ``fusion_threshold``
    backend option ie ``backend.set_options(fusion_threshold=10)``
  - |
    Changes ``fusion_threshold`` backend option to apply fusion when the
    number of qubits is above the threshold, not equal or above the threshold,
    to match the behavior of the OpenMP qubit threshold parameter.
