The OriginalValue property on a Field object indicates the value of a Field that existed in the record before any changes were made. This property returns a Variant.
oldValue = currentfield.OriginalValue
The OriginalValue property is used to return the original field value for a field from the current record.
In immediate update mode (the provider writes changes to the underlying data source once the Update method is called), the OriginalValue property returns the field value that existed prior to any changes (that is, since the last Update method call). This is the same value that the CancelUpdate method uses to replace the Value property.
In batch update mode (the provider caches multiple changes and writes them to the underlying data source only when the UpdateBatch method is called), the OriginalValue property returns the field value that existed prior to any changes (that is, since the last UpdateBatch method call). This is the same value that the CancelBatch method uses to replace the Value property. When this property is used with the UnderlyingValue property, you can resolve conflicts that arise from batch updates.