Hedera will be upgrading the Testnet to v0.12.0 (release notes: https://hedera.io/release-notes) on Friday, Feb 26th 2021 at 18:00 UTC. The restart will take approximately 2 hours to complete, during which time all network services on the Hedera Testnet will be offline. This upgrade should not affect your project's compatibility or data. As a precaution, we always recommend preserving project data prior to any Testnet upgrade.