ODK2 works in bi-directional

I am new to ODK2, is this work bi-directional, that is user and server interactive?

I haven’t explored much with ODK-X (the new name for ODK2) but from the documentation:

Bi-directional synchronization of data across devices. The ODK 2 tools support the collaborative sharing of survey data across devices, as well as the updating and submission of changes to previously collected data (for example: follow-up surveys) via a bi-directional synchronization protocol. This contrasts with the unidirectional device-to-server submission pathway of ODK Collect / ODK Aggregate / ODK Briefcase.

Can you provide some more details to your question?