What does the red edge of Luo Kangma mean?

It doesn't make any sense. It turns red because the system has been upgraded, as shown in the figure below:

"Luo Kang code" is an electronic certificate of personal health information based on personal health, which is declared by residents independently and verified by big data comparison. Residents of Luoyang (including permanent residents and temporary residents) and those who return to Luoyang should apply for "Luo Kang Code". People with health certificates can use the "Luo Kang code" in parallel.

Managers or operators of residential quarters (villages), government agencies and institutions, enterprises, shopping malls, supermarkets, commercial buildings, farmers' markets, financial outlets, scenic spots, hotels, railway stations, docks, airports, cultural and sports venues, buses, taxis and other public transport (including online car rides) shall check the health status of passers-by.

If it is found that the personnel marked with red team and yellow code are prohibited from entering or leaving (riding), immediately report to the competent department to take corresponding control measures and isolate them in places with temporary isolation conditions. The elderly, children and other people who have no intelligent terminal and can't apply for "Luo Kang code" can pass by community pass, health certificate or work certificate, and their body temperature is normal.