Hydra updates Mithril bootstrap tooling for the v2 backend

What happened

Hydra has updated its pinned Mithril distribution to 2630.0 and changed its cluster-download tooling and tutorial to request the v2 database backend. The change follows the removal of aggregator certification for the Cardano database v1 backend that Hydra downloads had previously used by default.

The update also removes a macOS `mithril-client-cli` fallback. According to the record, version 2630.0 now ships the client for all targets, including aarch64-darwin.

Why it matters

Teams using Hydra’s Mithril-based fast bootstrap need v2 backend downloads to remain compatible with the aggregator. Existing v1 download calls may no longer work where certification is required.

This is an operational tooling and dependency update for Hydra users, rather than a change to the Cardano node, ledger, protocol, or a hard fork.

What to watch

The practical receipt is whether Hydra’s v2-backed cluster and node download path continues to complete successfully with Mithril 2630.0. Operators relying on fast bootstrap should confirm their own tooling requests `--backend v2` rather than v1.