I have version 2.1.14. The documentation indicates you can set up a repeating task with several options. But, I cannot see any other option for due dates except setting a date, setting no date, and making the date a due by, due on, due after, or due optionally on. I do not see a menu or option for making the task a repeating task.
If you don't see 'Repeat' as a menu item then you haven't set it as one of your Fields. Go to 'Settings/Tasks/Fields & Defaults/Unused Fields and, using the striped handles to the right of each field, move the 'Repeat' field up to the 'Fields Used' section. Once it's moved, pressing the right pointing arrow will allow you set default values.
While you're in this view you might want to organise all the fields to your preference. It makes a real difference to day-to-day use.