Function zebra_chain::block::serialize::check_version

fn check_version(version: u32) -> Result<(), &'static str>

Checks if a block header version is valid.

Zebra could encounter a Header with an invalid version when serializing a block header constructed in memory with the wrong version in tests or the getblocktemplate RPC.

The getblocktemplate RPC generates a template with version 4. The miner generates the actual block, and then we deserialize it and do this check.

All other blocks are deserialized when we receive them, and never modified, so the deserialisation would pick up any errors.