New major version with focus in: A broader family of computation with classical logic. Introducing classical control flow, instructions, and data types to define circuits that include real-time computations on classical data. A kernel mechanism allows for opaque references to generic classical computations acting upon run-time data. Explicit timing, Introducing a flexible mechanism to describe design intent of instruction scheduling while remaining independent of specific durations determined by gate calibrations. This enables, for example, dynamical decoupling while retaining a gate-level description of a circuit. Embedded pulse-level definitions. An extensible mechanism to attach low-level definitions to gates. This is particularly relevant to calibration tasks which optimize pulse parameters using error amplification sequences most easily described at the gate level. Live doc https://qiskit.github.io/openqasm