An old slideshow made with a Templafy template can be updated with a new data in several ways.

Adjust date in the Master

Open Slide Master and correct the date on the top Slide of the list. The black slide also needs to be corrected.

Reuse slideshow

Open a new slideshow in Templafy with the current date. And select Reuse slides. Find the old slideshow. When inserted into the new slideshow, it will be updated with the new date.