What should the elderly do when they take the subway without their mobile phones?

Use a paper offline QR code, carry a valid ID inquiry machine, and seek the help of subway staff.

1. Use paper offline QR code: Some subway systems provide a paper version of offline QR code, also known as "application code" or "health code". You can go to the service center of the subway station or the relevant window to ask if you can provide a paper offline QR code and follow the instructions.

2. Carry a valid ID card inquiry machine: In the subway station, there will be a health code terminal inquiry machine. The elderly can carry valid ID cards or other certificates, verify their identity on the inquiry machine and inquire about health code information. Subway staff can assist the elderly to operate the inquiry machine to ensure that the elderly can pass the security check smoothly.

3. Seek the help of subway staff: If the elderly encounter difficulties or are unfamiliar with the operation, they can seek the help of subway staff. There will be staff on duty in the subway station, which can provide guidance and support to help the elderly get in and out of the station smoothly.