Yes, Ozhosting Cloud Backup Client works with retention policies. You can determine on task or file level for how many days you want to keep a file in your backup environment. During this period it will keep track of all the changes.

For example, if you make a backup once a day and retention is set on 30 days, the backup up data will have up to 30 versions. On the 31st day after the backup has run, the oldest version expires and is removed. If a file doesn't change, no new version is backed up, making the backup very efficient.