Following the launch of Photos in May 2015, Google began winding down similar functionality in Google+. A full deprecation of the remaining backup feature is now set for next month as older versions of the Android and iOS apps will stop working.
Google’s current image editing and storage solution has its roots in Google+. Installing the social network provided backups from your device, editing, and other social features. Those features were then replaced by Google Photos, with the older interface quickly removed after the 2015 launch.
However, it appears that the backup features remained in older versions of Google+. Google announced in an email today that on May 20, 2018 Android version 7.5 and older — as well as version 5.0 or older of the iOS client — will “no longer work.”
Google notes that “if you chose to have the photo backup setting enabled in Google+, your photos will no longer be backed up.” It encourages users to download or update to Google Photos to make sure backup is not interrupted in the transition.