Solana v1 is not live on mainnet yet, but unprepared infrastructure can fail in two ways.
RPC readers may freeze at the first v1 transaction. Fee sponsors may keep running while silently failing to enforce compute and priority-fee limits.
This is a compatibility issue, not a consensus flaw.
https://cryptoslate.com/hidden-solana-upgrade-bug-can-freeze-network-readers-and-silently-disable-fee-limits/