> For the complete documentation index, see [llms.txt](https://bitnet-whitepaper.gitbook.io/developer-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bitnet-whitepaper.gitbook.io/developer-docs/upgrades-overview/rollback.md).

# Rollback

### Rollback Procedure for BitNet Nodes

In rare cases where a chain upgrade fails or causes consensus issues, validators may need to **roll back to a previous BitNet version**.

The process involves restoring a valid database state and the signing state file to resume operations without triggering double-signing penalties.

***

#### ⚠What You Need to Roll Back

To perform a successful rollback, ensure you have the following:

1. A **backup of the node’s data directory**\
   Usually located at:

   ```bash
   ~/.bitnetd/data
   ```
2. A copy of `priv_validator_state.json`\
   This file tracks the last signed block and is **essential for avoiding double-signing**.

{% hint style="warning" %}
If `priv_validator_state.json` is missing, your validator risks signing the same block twice after rollback — leading to slashing.
{% endhint %}

***

#### Rollback Steps

**1. Stop Your Node**

Gracefully halt your BitNet validator:

```bash
bitnetd stop
```

***

**2. Restore from Backup**

Assuming you have a full backup in a folder named `backup/bitnetd/`:

```bash
rm -rf ~/.bitnetd/data
cp -r backup/bitnetd/data ~/.bitnetd/
```

Also ensure `priv_validator_state.json` is restored:

```bash
cp backup/bitnetd/data/priv_validator_state.json ~/.bitnetd/data/
```

***

**3. Install Previous BitNet Version**

From your BitNet source directory:

```bash
git fetch --all
git checkout <previous_version>
make install
```

Confirm the version:

```bash
bitnetd version --long
```

***

**4. Restart the Node**

Once the old binary and valid state are in place:

```bash
bitnetd start
```

The node will now resume operations from the last valid height **prior to the failed upgrade**.

***

#### If You Don't Have a Backup

If your validator lacks a data backup:

* Request a snapshot from another validator or trusted peer.
* Validate the database hash.
* Use the provided `priv_validator_state.json` if you can trust its accuracy.

***