# Upgrade 17 Jovian hardfork

> Notice date: December 19, 2025
>
> Target Network: GIWA Testnet (Sepolia)

## Overview

GIWA Chain will apply the Jovian hard fork (Upgrade 17 protocol update) from the OP Stack. This upgrade includes changes related to transaction fee calculations and block header fields, aiming to improve overall network stability and operational efficiency.

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Because this upgrade is a hardfork, it introduces protocol-level changes. Node operators must upgrade to the latest version before the scheduled activation time.
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## Schedule

* Testnet (Sepolia): *December 30, 2025 at 14:00:00 KST (Unix timestamp: 1767070800)*

## For Developers

* Changes to transaction fee calculations and certain block header fields (`extraData`, `blobGasUsed`) may require compatibility checks if your node, indexer, or tooling relies on these fields.

## For Node Operators

* Node operators must upgrade to the latest node version before the scheduled Jovian hard fork.
* For detailed information, please refer to the [giwa-io/node release notes.](https://github.com/giwa-io/node/releases/tag/v0.3.1)

## Learn more

Want to learn more about Upgrade 17? Check out the [OP Stack documentation](https://docs.optimism.io/notices/upgrade-17).