What does the short message of Shanghai Prevention and Control Office mean?

You can't. If you are new to Shanghai, it is to remind you to pay attention to epidemic prevention and control. If you stay in Shanghai, I will also send you this message, that is, the epidemic situation may change, so take precautions.

According to the current epidemic prevention risk, the epidemic prevention department may send a reminder message to the public for nucleic acid detection, and you may receive information from the municipal epidemic prevention department regardless of whether your health code is "green code" or "yellow code". Just take the initiative to repeatedly test nucleic acids.