Why is there a difference in REST API output format after migration from BPMS 6.4 to RHPAM 7.7?

Issue

• Why is there a difference in REST API output format after migration from BPMS 6.4 to RHPAM 7.7?

  Old URI: /business-central/rest/task/query?potentialOwner=dtc100557&status=Ready&status=Reserved&status=InProgress
  Before Migration:

  
  <task-summary-list-response>
  <task-summary>
  <id>10073</id>
  <name>Collections</name>
  <subject>
  </subject>
  <description>Task is in ECS queue</description>
  <status>Reserved</status>
  <priority>0</priority>
  <skipable>true</skipable>
  <actual-owner>dtC100557</actual-owner>
  <created-by>dtC100557</created-by>
  <created-on>2018-08-10T11:50:10.887+05:30</created-on>
  <activation-time>2018-08-10T11:50:10.887+05:30</activation-time>
  <process-instance-id>10059</process-instance-id>
  <process-id>Combo_BPM.ECS</process-id>
  <process-session-id>40050</process-session-id>
  <deployment-id>com.exide:Combo_BPM:1.1.80</deployment-id>
  <quick-task-summary>false</quick-task-summary>
  <parent-id>-1</parent-id>
  </task-summary>
  <task-summary>
  <id>140099</id>
  <name>NBUW_MyQueue</name>
  

  New URI: /kie-server/services/rest/server/queries/tasks/instances?potentialOwner=dtc100558&status=Ready&status=Reserved&status=InProgress
  After Migration:

  <org.kie.server.api.model.instance.TaskSummaryList>
  <tasks>
  <org.kie.server.api.model.instance.TaskSummary>
  <id>140113</id>
  <name>Client_Merge</name>
  <description>Task assigned to Customer Merge Queue</description>
  <status>Reserved</status>
  <priority>0</priority>
  <actualOwner>Administrator</actualOwner>
  <createdBy></createdBy>
  <createdOn>2020-04-14 11:45:50.973 UTC</createdOn>
  <activationTime>2020-04-14 11:45:50.973 UTC</activationTime>
  <processInstanceId>110087</processInstanceId>
  <processId>SprintV2_BPM.CustomerMerge</processId>
  <containerId>com.exide:SprintV2_BPM:1.0.42</containerId>
  <parentId>-1</parentId>
  </org.kie.server.api.model.instance.TaskSummary>
  <org.kie.server.api.model.instance.TaskSummary>
  <id>140112</id>
  <name>Client_Me