On the add asset form, when you select the Asset Type is Superannuation we allow you to Edit your historical concessional contributions.

This then impacts your Unused Carry-Forward Concessional Contributions

Your carry forward concessional contributions or unused concessional contributions cap for the previous five years, can be obtained from the ATO using MyGov.

Step 1

Login to MyGov (https://my.gov.au/)

Step 2

Access ATO

Step 3

Click the Super dropdown in the top menu and select either Concessional Contributions or Carry-Forward Concessional Contributions

Step 4

Select last year and you should see a box like the image below. Expand the "Show Details"

Step 5

From the show details section you can see a column for Concessional Contributions.