Aqarios Constrained Quantum Optimizer changelog

October 2026

The Constrained Quantum Optimizer is now available in the Qiskit Functions Catalog. See the Qiskit Functions changelog.

Breaking changes

Renamed the input parameter model to problem.
Renamed the output field obj_value to objective_value.
Replaced the postprocessing option with postprocessing_level, which takes an integer in the range [0, 3] instead of a string. The previous values map to "off" -> 0, "weak" -> 1, "medium" -> 2, and "strong" -> 3, and the default is unchanged at 3.
Restructured metadata.circuit_metrics. It now reports num_qubits, gate_count, depth, two_qubit_gate_count, two_qubit_gate_depth, and operations separately for before_transpilation and after_transpilation, instead of a single flat dictionary of averaged gate counts. The field is None when the problem was solved during preprocessing and no circuit was run (error code 4712).

Features

Added the seed_transpiler option to make circuit synthesis and routing reproducible across runs.
Added the job_tags option to attach your own tags to every Qiskit Runtime job the function submits.
Added the output field solution_bitstrings, which returns the same solutions as solutions in bitstring form.
Added metadata.solver_info.variable_mapping, which maps each variable name to its character position in the entries of solution_bitstrings.

Documentation

Documented that continuous (real-valued) variables are not supported and that integer variables require explicit bounds. Such models fail with error code 4710.