Migration Guide - Unreleased

Breaking changes committed since the last release, and how to update code that depends on them.

MONAI Physio prefers compatibility: public APIs are broken only when the change is generally beneficial to future users. When a break is unavoidable, the project does not ship deprecation shims or removed-symbol stubs. Instead, substantial changes ship with code that automates the conversion, and every break is recorded here in the commit that introduces it.

At release time this file is renamed migration_<version>.md and a fresh migration_next.md is started for the next cycle.

Entry template

Append one section per breaking change, newest last, using this shape:

## <symbol, module, or CLI flag> - <one-line summary>

**Change:** what moved, was renamed, or changed signature.

**Why:** the benefit to future users that justified the break.

**Before**

```python
old_call(argument)
```

**After**

```python
new_call(argument, required_option="value")
```

**Automated conversion:** `<path to script or CLI>`, or `None needed`.

InferPhysicsNeMoBase, InferPhysicsNeMoMGN, InferPhysicsNeMoMLP - model_tag is now a constructor argument

Change: model_tag moved from a class attribute to the first __init__ argument of InferPhysicsNeMoBase and its MGN and MLP subclasses (defaults "base", "mgn", "mlp"). log_level is now the second positional argument. A subclass that only sets a class-level model_tag now gets the constructor default instead, because __init__ assigns the instance attribute.

Why: the checkpoint tag must match the training method that wrote the weights (for example "physics_informed_motion"). It can now be chosen per instance without defining a subclass.

Before

class InferPhysicsInformed(InferPhysicsNeMoMGN):
    model_tag = "physics_informed_motion"


method = InferPhysicsInformed("DEBUG")

After

method = InferPhysicsNeMoMGN(model_tag="physics_informed_motion", log_level="DEBUG")

Automated conversion: None needed. Pass log_level by keyword and replace class-level model_tag overrides with the constructor argument.