Release Notes > COMSOL Multiphysics > Backward Compatibility with Version 4.3b

Backward Compatibility with Version 4.3b
Model Nodes are now Component Nodes
The Model nodes (as they were called in previous versions), which contained separate model components in a model file, are called Component nodes in version 5.2a.
Changes to Parametric Sweeps
Old models that use stationary parametric sweeps are loaded with the Reuse solution for previous step list set to Yes. The Run continuation for list is set to the parameter used, unless the continuation algorithm would not have been used for this model in previous versions (for example, if multiple parameters are used or if the parameter list is not monotonous).
Changes to the Physics Selection in Study Settings
The names of the states of a physics interface in the physics tree, which you can modify under Physics and Variables Selection in the study steps’ settings windows, have changed:
Provide Degrees of Freedom is now called Disable in Solvers.
Disable is now called Disable in Model.
Revised formulation for Laminar Inflow and Laminar Outflow
The formulations of the laminar inflow and laminar outflow conditions have been corrected. The modified formulation gives a more accurate mass flux. Some models may now produce a slightly different flow field.
Laminar inflow and laminar outflow are available in the fluid flow physics interfaces in the following modules:
New Default for Graphics Optimization
Under Graphics and Plot Windows in the Preferences dialog box, the default settings in the Optimize for list is now Quality instead of Performance.
Velocity/acceleration Integration variable
For the Solid Mechanics interface (and all related multiphysics interfaces) and the Truss interface, the help variable u0 (velocity integration variable) is used in Prescribed Velocity and Prescribed Acceleration features for Time Dependent study types. This variable computes the displacement for each point where the condition is prescribed. It is changed to use the full feature scope in order to avoid collisions in cases where several such features exist within the same model component. As a result, when opening and running an old model that uses such features together with a segregated solver, an error message appears, stating that not all dependent variables occur in at least one of the segregated solver steps. The relevant action is to manually add the velocity integration variable to the segregated step containing the corresponding displacement field. Alternatively, you can regenerate any affected solver sequence.
Math Libraries on AMD Processors
MKL is now the default math library on AMD processors. Switching to the ACML math library for AMD processors might improve performance in some cases.