Acronis True Image for Mac uses an "always incremental" archive meaning there is physically one file in the archive location while the incremental changes are written to this file directly as opposed to older formats where incremental changes were written into individual files in the backup location.
Acronis True Image 2017 stores 20 versions of backed up data in the backup file, any of them can be selected for recovery.
Acronis True Image 2016/2015 for Mac store 10 versions of backed up data in the backup file, any of them can be selected for recovery.