What is mustRotateKeysBefore in authorityMembers.members pallet?

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1

Hello,
Can someone remind me what is “mustRotateKeysBefore” in authorityMembers.members pallet ?
Thanks

2

expire_on_session is the authority membership expiration. It is updated as well as must_rotate_keys_before when session keys are updated.

However I don’t understand expire_on_session:

  • set_session_keys sets it to current + MaxOfflineSessions
  • when an authority is outgoing, when the next session begins, expire_on_session is set to current + MaxOfflineSessions, but only when there is no incoming authority.
  • I can’t find any other update: I guess it should be updated on ImOnline or at every session when the authority is active.