v8 upgrade problem w/ Elasticsearch

I am trying to upgrade 7.9.4 to 8.0.1 SugarPro.

Sugar 8.0.1 supports, and requires, an Elasticsearch upgrade.

Based on this:


We went with ES 6.2.1 for Sugar 8.0.1

Sysadmin set up a new VM for me with Elasticsearch 6.2.1 following instructions here:


When I attempt to point 7.9.4 to the new VM with ES 6.2.1 I get the following errors:


Tue Nov  6 14:12:45 2018 [9177][2053ed63-d2dc-52e8-0049-4ddab9fc33f1][FATAL] Elasticsearch: connection went away to elasticsearch-tst.mycompany.com:9200

Tue Nov  6 14:12:45 2018 [9177][2053ed63-d2dc-52e8-0049-4ddab9fc33f1][FATAL] Elasticsearch verify conn: failure

Tue Nov  6 14:12:45 2018 [9177][2053ed63-d2dc-52e8-0049-4ddab9fc33f1][FATAL] Elasticsearch no longer available


We verified that the sugar application server can see the ES server.


Now, I understand that 7.9.4 is not compatible with ES 6.2.1 but following the upgrade instructions it is recommended to point Sugar to a new, upgraded ES before upgrading to v8 and reindex - which is what I'm trying to do.. 


The errors seem to come from:


public function verifyConnectivity


public function onConnectionFailure

Now that same script has 

protected $allowedVersions = [


So, how do I get 7.9.4 to see ES 6.2.1?

What are my sysadmin and I missing?