# Altair Upgrade Scheduled and Merge Interop Testing Announced

DevFeed: [Altair Upgrade Scheduled and Merge Interop Testing Announced](<https://devfeed.tech/articles/finalized-no-29-16979.md>)

Original publisher: [Read original article](<https://blog.ethereum.org/en/2021/09/28/finalized-no-29>)

Author: Danny Ryan

Published: 2021-09-28T00:00:00Z

Content type: release

Language: en

Sources: [Ethereum Foundation Blog](<https://devfeed.tech/sources/ethereum-foundation-blog.md>)

Topics: [releases](<https://devfeed.tech/topics/releases.md>), [API](<https://devfeed.tech/topics/api.md>), [Software](<https://devfeed.tech/topics/software.md>), [Testing](<https://devfeed.tech/topics/testing.md>)

Tags: [api](<https://devfeed.tech/tags/api.md>), [releases](<https://devfeed.tech/tags/releases.md>), [research-development](<https://devfeed.tech/tags/research-development.md>), [software](<https://devfeed.tech/tags/software.md>), [test](<https://devfeed.tech/tags/test.md>), [upgrade](<https://devfeed.tech/tags/upgrade.md>)

## AI overview

The article announces that the Altair upgrade to the Beacon Chain is scheduled for October 27, 2021, and that mainnet client releases are in progress. It also describes the release of the Merge interoperability specification, with short-lived devnets planned for testing and refinement.

## Source excerpt

Altair is here; the Merge is coming. tl;dr Altair upgrade epoch set, mainnet client releases in progress 👀 Merge interop spec released. Devnets to follow 🏺...