Legacy tf.keras via tf_keras+TF_USE_LEGACY_KERAS vs. Migrating to Keras 3 for Model Loading Compatibility
When upgrading a TensorFlow environment from 2.15 to 2.16 or later, the default Keras implementation shifts from the in‑tree Keras 2 (tf.keras) to standalone Keras 3. This change affects how existing SavedModel and HDF5 files are deserialized, especially those that rely on custom objects or legacy preprocessing layers. The goal is to decide whether to preser