Backward Compatibility with Version 5.1

•	Plane Wave Radiation has been removed from the Linearized Potential Flow, Frequency Domain and Linearized Potential Flow, Transient interfaces in 1D axisymmetry.

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A new Lagrange multiplier variable (ta.lm_slip) has been added to the slip conditions in the Thermoacoustics, Frequency Domain interface. If you run a model with a segregated solver, you will need to add this variable to the group containing the velocity degree of freedom. You can also regenerate the default solver. In the API, you need to add comp1_ta_lm_slip to the declaration of the segregated step; for example, adding:

model.sol("sol1").feature("s1").feature("se1").feature("ss1").
set("segvar", new String[]{"comp1_p", "comp1_u", "comp1_T", "comp1_ta_lm_slip"});

•	The Waveguide end impedance option has been removed from 2D, 1D axisymmetric, and 1D as it had no physical meaning in these space dimensions.