Hedera will be upgrading the mainnet to v0.5.8 (release notes: https://hedera.io/release-notes
) on Thursday, June 18th, at 17:00 UTC. Nodes 2, 3, and 11 will be brought back online and node 5 (run by Hedera in GCP) will be replaced by a node run by Google. This upgrade will take approx. 150 minutes to complete, during which time all network services will be offline.