"Day Pass" mechanic was introduced in v1.16 and it's the new model for supporting 1010ti.me free.
The application will work as usual for free clock, meaning that you can use those free clocks as much as you want wherever you want that no nag will show.
If you use a non free clock (or downloaded clocks or edited free clocks) you are under "day pass" model.
If you are under day pass model, a nag will show up on the clock when the day pass is exhausted. It's not a real nag, it's just a message that will show up every 10 sec saying you must renew your day pass.