It is significant to be conscious that there are so many agencies running a business with expired licenses; do not study the lawful official procedures inflicted by the country act. In the same way, there are many cases of so-called trekking / touring agencies illegally activated by individuals & freelancers through their websites.
Booking your trip in advance with any trekking and travel agency, it is most important to know if the company has officially listed with the Nepal government authorities as well as other allowed travel associations of Nepal. Please; check following the official documents from Destination Himalaya Treks and Expedition.