def doWarnings():
    import twisted
    from twisted.python import versions
    if (twisted.version < versions.Version('twisted', 8, 0, 0)):
        LOG.warning("You should get Twisted 8 or later.  Previous versions "
                    "have some bugs that affect Dtella.")

    try:
        import dtella.bridge
    except ImportError:
        # Don't warn about GMP for clients, because verifying a signature
        # is fast enough without it (~1ms on a Core2)
        pass
    else:
        import Crypto.PublicKey
        try:
            import Crypto.PublicKey._fastmath
        except ImportError:
            LOG.warning("Your version of PyCrypto was compiled without "
                        "GMP (fastmath).  Signing messages will be slower.")