Good

// Check if Segregated Witness is Locked In
bool IsWitnessLockedIn(const CBlockIndex* pindexPrev, const Consensus::Params& params)
{
LOCK(cs_main);
return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_LOCKED_IN);
}

// BIP148 mandatory segwit signalling.
int64_t nMedianTimePast = pindex->GetMedianTimePast();
if ( (nMedianTimePast >= 1501545600) && // Tue 01 Aug 2017 00:00:00 UTC
(nMedianTimePast <= 1510704000) && // Wed 15 Nov 2017 00:00:00 UTC
(!IsWitnessLockedIn(pindex->pprev, chainparams.GetConsensus()) && // Segwit is not locked in
!IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus())) ) // and is not active.
{
bool fVersionBits = (pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS;
bool fSegbit = (pindex->nVersion & VersionBitsMask(chainparams.GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) != 0;
if (!(fVersionBits && fSegbit)) {
return state.DoS(0, error("ConnectBlock(): relayed block must signal for segwit, please upgrade"), REJECT_INVALID, "bad-no-segwit");
}
}