The solution to this is pretty simple:
While mininet is still running open a new terminal and type:
ovs-vsctl showThis should show result synonymous to that shown below;
root@sdn-0l:~# ovs-vsctl show e7fd4eea-afe3-4f9f-977c-86330374e7a5 Bridge "s1" Controller "ptcp:6634" Controller "tcp:10.100.1.61:6633" is_connected: true fail_mode: secure Port "s1-eth1" Interface "s1-eth1" Port "s1" Interface "s1" type: internal Port "s1-eth2" Interface "s1-eth2"As you can see the bridge value is "s1" in my case. Now run below to instruct the bridge to support current version protocols.
ovs-vsctl set bridge s1 protocols=OpenFlow10,OpenFlow12,OpenFlow13