Update README

Change-Id: Ib063f426067c98643a711a6b802f2ae685f9a7cd
diff --git a/trellis/README.md b/trellis/README.md
index e173418..9929757 100644
--- a/trellis/README.md
+++ b/trellis/README.md
@@ -4,7 +4,7 @@
 # Introduction
 This folder contains Mininet scripts and corresponding config files that
 can be used to emulate Trellis leaf-spine fabric, vRouter and DHCP relay.
-Current Mininet setup only works with ONOS 1.11 and above. We recommend you use the tip of 1.11 branch.
+Current Mininet setup only works with ONOS 1.12 and above. We recommend you use the tip of 1.12 branch.
 
 # Download
 `git clone https://gerrit.onosproject.org/routing`