> ## Documentation Index
> Fetch the complete documentation index at: https://docs.base.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Upgrades

> Track Base network upgrades, activation dates, and the protocol changes included in each release.

Base evolves through named network upgrades. Each release introduces protocol changes, new features, or parameter updates that activate across Base Sepolia and Base Mainnet.

Base upgrade dates follow the [Base Chain upgrades tracker](https://chain.base.org/upgrades). A month without a confirmed activation timestamp is a planning target and may change.

## Base Network Upgrades

<Update label="November 2026" tags={["Planning", "Base upgrade"]}>
  ## [Denim](/upgrades/denim/200ms-blocks)

  Denim introduces native blocks at a 200ms cadence, millisecond-resolution RPC timestamps, and onchain millisecond time through BaseTime.

  * **Base Sepolia:** Targeting November 2026
  * **Base Mainnet:** Targeting November 2026

  [View the Denim specification](/upgrades/denim/200ms-blocks)
</Update>

<Update label="September 2026" tags={["Planning", "Base upgrade"]}>
  ## [Cobalt](/upgrades/cobalt/overview)

  Cobalt adds native account abstraction with EIP-8130, improves the B20 token standard, and introduces dynamic node upgrades.

  * **Base Sepolia:** Targeting September 2026
  * **Base Mainnet:** Targeting September 2026

  [View Cobalt features](/upgrades/cobalt/overview)
</Update>

<Update label="June 25, 2026" tags={["Live", "Base upgrade"]}>
  ## [Beryl](/upgrades/beryl/overview)

  Beryl makes Base a first-class issuance platform with B20 tokens, reduces withdrawal delays, and adopts Reth V2 as the reference execution client.

  * **Base Sepolia:** Activated June 18, 2026
  * **Base Mainnet:** Activated June 25, 2026

  [View Beryl features](/upgrades/beryl/overview)
</Update>

<Update label="May 28, 2026" tags={["Live", "Base upgrade"]}>
  ## [Azul](/upgrades/azul/overview)

  Azul is Base's first independent network upgrade. It strengthens security and decentralization, advances the path to 1 gigagas per second, and improves the developer experience.

  * **Base Sepolia:** Activated April 20, 2026
  * **Base Mainnet:** Activated May 28, 2026

  [View Azul features](/upgrades/azul/overview)
</Update>

## Upstream OP Stack Hardforks

Base adopted the following upstream OP Stack hardforks. Entries are ordered by Base Mainnet activation date.

<Update label="December 2, 2025" tags={["Live", "OP Stack"]}>
  ## [Jovian](/upgrades/jovian/overview)

  Jovian introduces a configurable minimum base fee and a data availability footprint gas scalar for improved fee-market stability.

  * **Base Sepolia:** Activated November 19, 2025
  * **Base Mainnet:** Activated December 2, 2025

  [View Jovian changes](/upgrades/jovian/overview)
</Update>

<Update label="May 9, 2025" tags={["Live", "OP Stack"]}>
  ## [Isthmus](/upgrades/isthmus/overview)

  Isthmus incorporates Ethereum Pectra EIPs and introduces the operator fee mechanism for sequencer revenue.

  * **Base Sepolia:** Activated April 17, 2025
  * **Base Mainnet:** Activated May 9, 2025

  [View Isthmus changes](/upgrades/isthmus/overview)
</Update>

<Update label="January 9, 2025" tags={["Live", "OP Stack"]}>
  ## [Holocene](/upgrades/holocene/overview)

  Holocene introduces dynamic EIP-1559 parameters configurable through `SystemConfig` and stricter block derivation rules.

  * **Base Sepolia:** Activated November 26, 2024
  * **Base Mainnet:** Activated January 9, 2025

  [View Holocene changes](/upgrades/holocene/overview)
</Update>

<Update label="September 11, 2024" tags={["Live", "OP Stack"]}>
  ## [Granite](/upgrades/granite/overview)

  Granite adds `bn256Pairing` precompile input-size restrictions and updates the channel timeout parameter.

  * **Base Sepolia:** Activated August 12, 2024
  * **Base Mainnet:** Activated September 11, 2024

  [View Granite changes](/upgrades/granite/overview)
</Update>

<Update label="July 10, 2024" tags={["Live", "OP Stack"]}>
  ## [Fjord](/upgrades/fjord/overview)

  Fjord introduces FastLZ-based L1 fee estimation, the RIP-7212 `secp256r1` precompile, and Brotli channel compression.

  * **Base Sepolia:** Activated May 29, 2024
  * **Base Mainnet:** Activated July 10, 2024

  [View Fjord changes](/upgrades/fjord/overview)
</Update>

<Update label="March 14, 2024" tags={["Live", "OP Stack"]}>
  ## [Ecotone](/upgrades/ecotone/overview)

  Ecotone integrates Ethereum Dencun changes, including EIP-4844 blob transactions and EIP-4788 beacon block roots.

  * **Base Sepolia:** Activated February 21, 2024
  * **Base Mainnet:** Activated March 14, 2024

  [View Ecotone changes](/upgrades/ecotone/overview)
</Update>

<Update label="February 22, 2024" tags={["Live", "OP Stack"]}>
  ## [Delta](/upgrades/delta/overview)

  Delta introduces span batches to reduce L1 data costs by compressing multiple L2 blocks into a single batcher transaction.

  * **Base Sepolia:** Activated December 22, 2023
  * **Base Mainnet:** Activated February 22, 2024

  [View Delta changes](/upgrades/delta/overview)
</Update>

<Update label="January 11, 2024" tags={["Live", "OP Stack"]}>
  ## [Canyon](/upgrades/canyon/overview)

  Canyon brings Ethereum Shanghai EIPs, including EIP-3651, EIP-3855, and EIP-3860, to the Base execution layer.

  * **Base Sepolia:** Activated November 14, 2023
  * **Base Mainnet:** Activated January 11, 2024

  [View Canyon changes](/upgrades/canyon/overview)
</Update>

## Other Changes

The [configuration changelog](/base-chain/network-information/configuration-changelog) tracks network parameter changes that do not belong to a specific upgrade.