Box uses file versioning, but the API does not explicitly provide version numbers. These functions use modified_date as a proxy to determine a version number (version_no), which you can use with box_dl() and box_read().
box_previous_versions(): data.frame describing previous versions of file.
box_version(): integer version number of most-recent version of file.
Details
box_version_history(), previously called box_previous_versions(), gets information on all previous versions of a file. If there are no previous versions, this function returns NULL.
box_version_number() gets the version number of the most-recent version.
To access the Box version API itself, you can use box_version_api().
References
This function is a light wrapper of the box.com API versions method.