SIMD-0249: Delay Commission Updates

proposals/0249-delay-commission-updates.md

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+---
+simd: '0249'
+title: Delay Commission Updates
+authors: Justin Starry (Anza)
+category: Standard
+type: Core
+status: Review
+created: 2025-02-18
+feature: (fill in with feature key and github tracking issues once accepted)
+---
+
+## Summary
+
+Allow validators to update their commission rate at any time but delay those
+commission updates for at least one full epoch.
+
+## Motivation
+
+Validators should be able update their desired commission at any time. That
+said, stake delegators should always have ample time to re-delegate their stake
+in response to validator commission rate changes.
+
+## New Terminology
+
+NA
+
+## Detailed Design
+
+### Runtime
+
+For a given epoch `E`, the earned inflation rewards for each vote account are
+calculated at the beginning of the next epoch `E + 1`. During inflation reward
+calculation, use the inflation rewards commission rate from the vote account
+state as it existed at the beginning of epoch `E - 1`. If the vote account did
+not exist at that time, fall back to the vote account state at the beginning of
+epoch `E`. And if the vote account did not exist then either, fall back
+to the vote account state at the beginning of epoch `E + 1`.
+
+#### UpdateCommission
+
+Update the core vote program to no longer restrict commission increases from
+happening during the first half of the epoch.
+
+## Alternatives Considered
+
+NA
+
+## Impact
+
+- Validators will need to wait at least one full epoch before their commission
+updates are applied.
+
+- Stake delegators will have at least one full epoch to react to commission
+updates.
+
+## Security Considerations
+
+NA
+
+## Drawbacks *(Optional)*
+
+Why should we not do this?
+
+## Backwards Compatibility *(Optional)*
+
+A feature gate will be used to simultaneously update vote program rules around
+commission rate updates as well as update the runtime's commission calculations
+at epoch boundaries.