[Runtime] RT4300 Schedule

Development Runtime upgrades
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We are planning to release Runtime 4300/4301 in all network(s) following the schedule below:

Moonbase Alpha
Runtime: 4300
When: April 8, 2026

Moonriver
Runtime: 4300
When: May 12, 2026 at approximately 13:00:00 UTC
Block: ~ 16,249,119

Moonbeam
Runtime: 4301*
When: May 20, 2026 at approximately 13:00:00 UTC
Block: ~15,677,123

* Note: runtime 4301 will contain a fix to remove the EIP-7825 default gas limit of16_777_216restriction for transactions and set it to 35_000_000. This change will be applied to Moonbase Alpha and Moonriver in RT4400.

This runtime upgrade includes several breaking changes.
See the release note for more details: Releases · moonbeam-foundation/moonbeam · GitHub

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Summary of Changes

Moonbeam Runtime 4300 — What it means for you

Runtime 4300 upgrades Moonbeam to a newer Polkadot-SDK version and includes fixes across XCM, Ethereum RPCs, and staking.

:star: Core updates

  • Upgraded Moonbeam to Polkadot-SDK stable2512.

:warning: Notable changes

  • Unprotected Ethereum transactions are now forbidden.

  • Fixed issues with eth_getBlockByNumber("latest") returning null and improved WS RPC stability.

  • Permit deadlines are now checked in milliseconds, aligning with expected behavior.

:gear: XCM updates

  • Re-enabled the UniversalOrigin XCM instruction.

  • Fixed XCM refund logic and benchmarking issues.

:wrench: Other improvements

  • Added delegation scheduled requests summary in staking.

  • Regenerated runtime weights.

For full details, see the release notes:
https://github.com/moonbeam-foundation/moonbeam/releases/tag/runtime-4300

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