Method for handling validator set churn #860
Description
If the validator sets registered on external EVM chains fall sufficiently far out of date with the active validator sets on Avalanche, it could become impossible to construct a valid ICM signature from a given chain (due to the old validators going offline).
For this issue, determine and document the approach for preventing this situation. Possibilities include:
- Heart beat messages requirements
- Max churn requirements
- Persisting of individual validator signatures