def is_version_compatible(from_version: int, to_version: int) -> bool:
    """
    Return whether it is possible to perform compatible version negotiation
    from `from_version` to `to_version`.
    """
    # Version 1 is compatible with version 2 and vice versa. These are the
    # only compatible versions so far.
    return set([from_version, to_version]) == set(
        [QuicProtocolVersion.VERSION_1, QuicProtocolVersion.VERSION_2]
    )

    Return whether it is possible to perform compatible version negotiation
    from `from_version` to `to_version`.
    
src/aioquic/quic/connection.py