---
title: 2.0.x
canonical: 'https://lightning.ai/docs/pytorch/stable/home/migration_guide/from_2_0'
---
# 2.0.x {#2-0-x}

## Regular User {#regular-user}

| If | Then | Ref |
| --- | --- | --- |
| used PyTorch 1.11 | upgrade to PyTorch 2.1 or higher | [PR18691](https://github.com/Lightning-AI/pytorch-lightning/pull/18691) |
| called `self.trainer.model.parameters()` in `LightningModule.configure_optimizers()` when using FSDP | On PyTorch 2.0+, call `self.parameters()` from now on | [PR17309](https://github.com/Lightning-AI/pytorch-lightning/pull/17309) |
| used `Trainer(accelerator="tpu", devices=[i])"` to select the 1-based TPU core index | the index is now 0-based | [PR17227](https://github.com/Lightning-AI/pytorch-lightning/pull/17227) |
| used `torch_xla < 1.13` | upgrade to `torch_xla >= 1.13` | [PR17368](https://github.com/Lightning-AI/pytorch-lightning/pull/17368) |
| used `trainer.num_val_batches` to get the total size of all validation dataloaders | use `sum(trainer.num_val_batches)` | [PR18441](https://github.com/Lightning-AI/pytorch-lightning/pull/18441) |
| used `trainer.num_test_batches` to get the total size of all test dataloaders | use `sum(trainer.num_test_batches)` | [PR18441](https://github.com/Lightning-AI/pytorch-lightning/pull/18441) |
| used `trainer.num_sanity_val_batches` to get the total size of all validation dataloaders for sanity checking | use `sum(trainer.num_sanity_val_batches)` | [PR18441](https://github.com/Lightning-AI/pytorch-lightning/pull/18441) |
| used `Trainer(devices="auto")` to auto-select all available GPUs in a Jupyter notebook | use `Trainer(devices=-1)` | [PR18291](https://github.com/Lightning-AI/pytorch-lightning/pull/18291) |
| used `Trainer(devices="auto")` to auto-select all available GPUs in a Jupyter notebook | use `Trainer(devices=-1)` | [PR18291](https://github.com/Lightning-AI/pytorch-lightning/pull/18291) |
| `pip install lightning` to install `lightning.app` dependencies | use `pip install lightning[app]` if you need `lightning.app` | [PR18386](https://github.com/Lightning-AI/pytorch-lightning/pull/18386) |

## Advanced User {#advanced-user}

| If | Then | Ref |
| --- | --- | --- |
| used the `torchdistx` package and integration in Trainer | materialize the model weights manually, or follow our [guide for initializing large models](/docs/pytorch/2.6.6/reference/advanced/model_init.md) | [PR17995](https://github.com/Lightning-AI/pytorch-lightning/pull/17995) |
| defined `def training_step(self, dataloader_iter, batch_idx)` in LightningModule | remove `batch_idx` from the signature and expect `dataloader_iter` to return a triplet `(batch, batch_idx, dataloader_idx)` | [PR18390](https://github.com/Lightning-AI/pytorch-lightning/pull/18390) |
| defined `def validation_step(self, dataloader_iter, batch_idx)` in LightningModule | remove `batch_idx` from the signature and expect `dataloader_iter` to return a triplet `(batch, batch_idx, dataloader_idx)` | [PR18390](https://github.com/Lightning-AI/pytorch-lightning/pull/18390) |
| defined `def test_step(self, dataloader_iter, batch_idx)` in LightningModule | remove `batch_idx` from the signature and expect `dataloader_iter` to return a triplet `(batch, batch_idx, dataloader_idx)` | [PR18390](https://github.com/Lightning-AI/pytorch-lightning/pull/18390) |
| defined `def predict_step(self, dataloader_iter, batch_idx)` in LightningModule | remove `batch_idx` from the signature and expect `dataloader_iter` to return a triplet `(batch, batch_idx, dataloader_idx)` | [PR18390](https://github.com/Lightning-AI/pytorch-lightning/pull/18390) |
| used `batch = next(dataloader_iter)` in LightningModule `*_step` hooks | use `batch, batch_idx, dataloader_idx = next(dataloader_iter)` | [PR18390](https://github.com/Lightning-AI/pytorch-lightning/pull/18390) |
| relied on automatic detection of Kubeflow environment | use `Trainer(plugins=KubeflowEnvironment())` to explicitly set it on a Kubeflow cluster | [PR18137](https://github.com/Lightning-AI/pytorch-lightning/pull/18390) |

## Developer {#developer}

| If | Then | Ref |
| --- | --- | --- |
| used the `XLAStrategy.is_distributed` property | it was removed because it was always True | [PR17381](https://github.com/Lightning-AI/pytorch-lightning/pull/17381) |
| used the `SingleTPUStrategy.is_distributed` property | it was removed because it was always False | [PR17381](https://github.com/Lightning-AI/pytorch-lightning/pull/17381) |

---

**Navigation**

- Parent: [2.0 Upgrade Guide](/docs/pytorch/2.6.6/home/migration_guide.md)