Work Definition ERES doesn't capture the changes made to previous version separately.

Summary:

We have enabled ERES for Work Definition.

When a new version of Work Definition is created and routed for approvals then a PDF attachment goes with approval notification. Attachment has latest version of WD which will be effective once approved and previous version of WD which is getting end dated. However, there is no way to identify what all changes have been made to previous version. Work Definition has many details and it is almost impossible for approver to identify what changes have been made ?

I checked Audit table. There is no value in column 'Old value' .For example: in version1, Ing qty was 10. Now in new version 2, it has been changed from 10 to 12 then in Audit table, 'Old Value' column is blank.