google-drive-ruby 1.x.x depends on google-api-client 0.8.x and Google Drive API V2.
google-drive-ruby 2.x.x depends on google-api-client 0.9.x and Google Drive API V3.
Each of them involves incompatible API changes. The users of google-drive-ruby may be affected by these changes.
Here are some changes likely affecting google-drive-ruby users:
If you pass an instance of Google::APIClient to GoogleDrive.login_with_oauth, it will no longer work, because Google::APIClient.new was removed. You need to pass credentials generated by googleauth library instead.
The field "title" in search queries was renamed to "name". e.g.,
session.files(q: "title = 'hoge'")
must be rewritten to:
session.files(q: "name = 'hoge'")
Ver. 0.x.x no longer works, because the API used was deprecated and shut down. You need to migrate to ver. 1.x.x or later.
Ver. 1.x.x is not 100% backward compatible with 0.x.x. Some methods have been removed. Especially, GoogleDrive.login has been removed, and you must use GoogleDrive.saved_session or GoogleDrive.login_with_oauth instead, as in the example code in README.md.