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

# Delta

> Hardfork registry entry for the Delta network upgrade, which introduced span batches.

<Info>
  **Normative spec:** the [Delta specification](https://specs.optimism.io/protocol/delta/overview.html)
  is the canonical definition of this upgrade. This page records activation data
  and operational pointers; it does not restate the spec.
</Info>

Delta consisted of a single consensus-layer feature: span batches, which reduce
the fixed per-block overhead of batch submission.

|                                         |                                                                                           |
| --------------------------------------- | ----------------------------------------------------------------------------------------- |
| Status                                  | Active                                                                                    |
| Governing spec                          | [specs.optimism.io](https://specs.optimism.io/protocol/delta/overview.html)               |
| Governance approval                     | [proposal](https://gov.optimism.io/t/final-upgrade-proposal-3-delta-network-upgrade/7310) |
| Mainnet activation (superchain default) | Thu, 22 Feb 2024 00:00:00 UTC (`1708560000`)                                              |
| Sepolia activation (superchain default) | Fri, 22 Dec 2023 00:00:00 UTC (`1703203200`)                                              |

## What changed

Per the [spec overview](https://specs.optimism.io/protocol/delta/overview.html):

* Consensus layer: [span batches](https://specs.optimism.io/protocol/delta/span-batches.html).
  Delta is specified only in the rollup node (`delta_time`); it required no
  execution-engine change.