The phrase refers to acquiring a specific application file, packaged in APK (Android Package Kit) format, for a previous iteration of the 1688 mobile platform. These files enable users to install older software versions on their Android devices, typically outside of official app store distribution channels.
Accessing a legacy build can be beneficial in scenarios such as compatibility issues with newer operating systems, hardware constraints, or user preference for a feature set present in a prior release but subsequently removed. Historically, users might seek older versions to circumvent enforced updates or access features no longer supported in the current official application.