Since our account upgraded to the new ID Merge Mixpanel, createAlias did not appear to function, or even register in the live data in Mixpanel.

e.g.
$mixpanel->createAlias($original_id, $wf_user_distinct_id);

doesn't result in an alias'd account or generate a Create Alias event in Mixpanel

$data = array(	'event' => '$create_alias'	,	'properties' => array(	'distinct_id' => $original_id	,	'alias' => $wf_user_distinct_id	,	'token' => '...'	)	); 

and sending it over to api.mixpanel/track works totally fine