The problem description does not give a precise description on the format of the version, which makes it necessary to do try-and-error. In addition, its vague description misleads the reader to think it follows a major.minor format, which is not the case.
Without a concise format definition, it is impossible to get it right in the first attempt, considering the variety of versioning schemes out there. Such description might be acceptable during a on-site interview where clarification can be done promptly. But not for such online tests.