// start bitcoindA (v0.16.3)
$ /home/zono/bitcoinA/src/bitcoind -server -listen -port=17591 -rpcuser=bitcoinrpc -rpcpassword=bitcoinrpcpass -rpcport=16591 -datadir=$HOME/regtest/A/ -connect=localhost:17592 -regtest -pid=$HOME/regtest/A/.pid -daemon -debug

// start bitcoindB (v0.14.3)
$ /home/zono/bitcoinB/src/bitcoind -server -listen -port=17592 -rpcuser=bitcoinrpc -rpcpassword=bitcoinrpcpass -rpcport=16592 -datadir=$HOME/regtest/B/ -connect=localhost:17591 -regtest -pid=$HOME/regtest/B/.pid -daemon -debug

// generate a block on bitcoindA
$ ./bitcoin/src/bitcoin-cli -rpcuser=bitcoinrpc -rpcpassword=bitcoinrpcpass -rpcport=16591 -regtest generate 1

// check log on bitcoindB
$ tail -f /home/zono/regtest/B/regtest/debug.log

2019-01-27 03:36:27 Requesting block 086e6b0cdb854c4ffa08033af35a0a5866aebf1fe72195805401c4e7692861cb (1) peer=0
2019-01-27 03:36:27 sending getdata (37 bytes) peer=0
2019-01-27 03:36:27 received: block (262 bytes) peer=0
2019-01-27 03:36:27 received block 086e6b0cdb854c4ffa08033af35a0a5866aebf1fe72195805401c4e7692861cb peer=0
2019-01-27 03:36:27 ERROR: AcceptBlock: unexpected-witness, ContextualCheckBlock : unexpected witness data found (code 16)
2019-01-27 03:36:27 Misbehaving: 127.0.0.1:52872 peer=0 (0 -> 100) BAN THRESHOLD EXCEEDED
2019-01-27 03:36:27 ERROR: ProcessNewBlock: AcceptBlock FAILED
2019-01-27 03:36:27 sending reject (58 bytes) peer=0
2019-01-27 03:36:27 Warning: not banning local peer 127.0.0.1:52872!