Good day, 

Unfortunately you can only do the uif declaration for the period you are processing.

If you want to do previous periods declarations you will have to roll back to the period you want to submit for, but then you will lose all processing done to date.

You can also not roll back to a previous tax year so we do not advise to roll back.

You can manually do the submission on u-filing for the periods not declared which is what we advise to do.

Regards, 
Luanne