Please also note the supported file types in New Standard Assignment:
After you select to create a new Turnitin assignment from your class, please click on the Standard Assignment title with the “Classic” label in the top right corner to go on the current one.
However, you are encouraged to take time trying the new edition before the existing one phased out. If you wanted to do so, a blue banner at the top of the landing screen indicates that there is a new version of the Standard Assignment available. Select the “Try Now” button.