The Zhaga D4i smart controller is custom-designed for the Energy Management System (EMS) and streetlight control retrofit projects in the Turkish market. Customer feedback indicates that after nearly four years of field operation, the product’s physical performance remains stable, with no signs of condensation or external water ingress, demonstrating excellent durability and long-term reliability. This feedback fully validates Long-Join’s high-quality and performance assurance under harsh conditions, reflecting the company’s technological leadership and customer trust in the smart street lighting field. This case strongly supports the broad application and promotion of Long-Join controllers in international smart lighting projects.