> ## Documentation Index
> Fetch the complete documentation index at: https://monadfoundation-40611fb6-devops-1498-direct-udp-implementat.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# v0.16.1 Upgrade Instructions

<Warning>
  These instructions apply to **mainnet** and **testnet**. Always verify which network you are operating before proceeding.
</Warning>

## Upgrade notes

No breaking changes to `node.toml` config for `v0.16.1`.

**Metrics endpoint enabled by default.** Since v0.16.0, the metrics endpoint is enabled by default on port `9143/TCP`, listening on `0.0.0.0`. If you have firewall rules restricting the metrics port, verify they are configured as expected.

<Warning>
  **MONAD\_TEN activation on mainnet (MIP-8: page-encoded storage)**

  v0.16.1 activates MONAD\_TEN on **mainnet** at timestamp `1788359400` (2026-09-02 14:30 UTC).

  **Every mainnet node must be running v0.16.1 before that timestamp.** A node still on v0.16.0 or earlier will continue applying MONAD\_NINE rules after activation and will diverge from the network.

  All nodes **must** also be in dual-db mode (Phase A complete) before upgrading. See [MIP-8 Activation and Page Storage Migration](/node-ops/upgrade-instructions/page-storage-mip-8-migration) for details.

  **Nodes that have not completed Phase A (dual-db activation) will fail to start on v0.16.1.** v0.16.1 extends the page-encoded timeline assertion from testnet to mainnet — if neither a page-encoded primary (Phase C) nor an active secondary timeline (Phase A/B) is detected, the node aborts at startup with:

  ```
  live monad requires a page-encoded timeline (as primary or secondary) on monad_mainnet; primary_is_page=0 secondary_active=0
  ```

  Note that this failure surfaces at **upgrade time**, not at the activation timestamp. Verify dual-db status across your fleet before you begin.
</Warning>

## 1. SSH into the node as `root` user

## 2. Verify dual-db mode (Phase A)

Before upgrading, confirm your node has completed Phase A (dual-db activation). Nodes without an active page-encoded timeline will fail to start on v0.16.1.

```bash theme={null}
monad-mpt --storage /dev/triedb
```

You should see both Primary and Secondary timelines:

```
Active timelines:
     Primary:
        State machine kind: ethereum
     Secondary:
        State machine kind: monad
```

If you only see a single `ethereum` Primary timeline, complete the [Phase A migration](/node-ops/upgrade-instructions/page-storage-mip-8-migration#phase-a-page-activation) before proceeding.

## 3. Stop services

```bash theme={null}
sudo systemctl stop monad-bft monad-execution monad-rpc
```

## 4. Upgrade monad package

<Warning>
  If you encounter issues with the GPG signature (e.g. signatures were invalid), please renew the keys with the command below.
</Warning>

```bash theme={null}
curl -fsSL https://pkg.category.xyz/keys/public-key.asc \
  | gpg --dearmor --yes -o /etc/apt/keyrings/category-labs.gpg
```

```bash theme={null}
sudo apt update && sudo apt install --reinstall monad=0.16.1 -y --allow-downgrades --allow-change-held-packages
sudo apt-mark hold monad
```

<Warning>
  The `apt-mark hold monad` command prevents the monad package from being upgraded automatically by `apt-get upgrade`. Without it, unattended system upgrades can install a newer version of monad that has not been approved for your network, causing version mismatch issues.
</Warning>

## 5. Start services and verify

```bash theme={null}
sudo systemctl start monad-bft monad-execution monad-rpc
sudo systemctl status monad-bft monad-execution monad-rpc --no-pager -l
```

All services should show `Active: active (running)`. Confirm the node rejoins and advances blocks.

If `monad-execution` exits immediately, check the journal for the page-encoded timeline assertion described in the upgrade notes above — that indicates Phase A was not completed on this node.

## 6. Verify the correct version is running

```bash theme={null}
monad-rpc -V
```

Expected output:

```json theme={null}
monad-rpc {"commit":"12b7017d61e888a62d89978d623fed182297e7af","tag":"v0.16.1","branch":"","modified":true}
```