in v0.12 https://github.com/bitcoin/bitcoin/pull/7081 (by @luke-jr) was merged adding `-bytespersigop` (with default of 20).

this is preventing simple bare multisig transactions from being accepted into mempool when the size is < 400 bytes.  
eg; https://gist.github.com/rubensayshi/ac4f617207f7a50559e85d61c05800be

from 1-of-7 and onwards they are accepted because the ratio of bytes:sigops is high enough.  
also having 2 or more inputs will work because it again tips the ratio of bytes:sigops over.

the reason mainly being that `GetLegacySigOpCount` calls `GetSigOpCount` with `fAccurate=false`.

It looks like changing `GetLegacySigOpCount` to use `fAccurate=true` would cause side effects in the few other places (`ConnectBlock`, `CheckBlock`, `CreateNewBlock`) and simply adding `fAccurate` as arg to `GetLegacySigOpCount` would affect the value stored in `CTxMemPoolEntry.sigOpCount` which in turn affects a bunch of other things.

}
        if (pfrom->nVersion < MIN_PEER_PROTO_VERSION)
        {
            
            LogPrintf("peer=%d using obsolete version %i; disconnecting\n", pfrom->id, pfrom->nVersion);
            pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE,
                               strprintf("Version must be %d or greater", MIN_PEER_PROTO_VERSION));
            pfrom->fDisconnect = true;
            return false;
        }
        if (pfrom->nVersion == 10300)
            pfrom->nVersion = 300;
        if (!vRecv.empty())
            vRecv >> addrFrom >> nNonce;
        if (!vRecv.empty()) {
            vRecv >> LIMITED_STRING(pfrom->strSubVer, MAX_SUBVERSION_LENGTH);
            pfrom->cleanSubVer = SanitizeString(pfrom->strSubVer);
        }
        if (!vRecv.empty()) {
            vRecv >> pfrom->nStartingHeight;
        }
        {
            LOCK(pfrom->cs_filter);
            if (!vRecv.empty())
                vRecv >> pfrom->fRelayTxes; 
            else
                pfrom->fRelayTxes = true;
        }
        
        if (nNonce == nLocalHostNonce && nNonce > 1)