What is the ruling of the outings (Ar. khuruj1) practiced by the Jama‘at al-Tableegh wa al-Da‘wah group? Is it an innovation?

These outings are permissible for those who are qualified to call others to Allah, provided that they are pleasant with people; employ wisdom, fair admonishment, and kindness when calling them; that they are merciful with others; and that they are knowledgeable of what they enjoin and forbid. A prerequisite [to it being permissible] is that they do not neglect their families and their dependents. Limiting the khuruj to 4 days, 40, or some other number, is purely a matter of organization and logistics. It has no connection to the issue of innovation, unless its followers believe otherwise.

Allah Mighty and Most High knows best.