Sign and Submit the Config Update

Update proto as the Org1 Admin in Server1

docker exec -it cli bash

Inside the bash:

peer channel signconfigtx -f org4_update_in_envelope.pb

Update it as the Org2 in Server2 and Server3

docker exec -it org2cli bash
docker exec -it org3cli bash

Inside both Server2 and Server3 bash first export CHANNEL_NAME and ORDERER_CA variables:

export ORDERER_CA=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem && export CHANNEL_NAME=mychannel

Then:

peer channel update -f org4_update_in_envelope.pb -c $CHANNEL_NAME -o orderer.example.com:7050 --tls --cafile $ORDERER_CA