Modification to downtime window.

We propose increasing SignedBlocksWindow from 5000 to 22,500.

Currently SignedBlocksWindow is 5000 and MinSignedPerWindow is 50%.

Therefore validators must sign at least 2500 blocks out of the last 5000 blocks to prevent being slashed because of downtime.

With the current block time of 6.4 seconds, validators cannot be offline for more than 4.4 hours.

If this proposal will pass:

Validators will be able to sign at least 11,250 blocks out of the last 22,500 blocks to prevent being slashed because of downtime.

Validators will be able to be offline for 19.8 hours at a time without being slashed, which will give more time for maintenance and chain updates. If the network ends up hitting a target avg blocktime of 6 seconds, then Validators will be able to be offline for 18 hours at a time.

This would bring us in line with the window for downtime on the CosmosHub & SentinelHub.

These changes have been discussed without any major objections in https://t.me/secretgovernance and on the April 21, 2021 Secret Governance call. You can also track the information on the forums here https://forum.scrt.network/t/modification-to-downtime-window-proposal/3250?u=moonstash