I had been using rclone (https://rclone.org/) for Amazon S3, which has some of the same features but recently the application key was blocked by Amazon. Is duplicacy safe from the same fate?
I think Amazon only blocked rclone's application key for Amazon Drive. There is no way for Amazon to prevent a third-party application from accessing S3, since users provide their own S3 credentials and Amazon doesn't know who is on the other side.