Earlier this year, on March 2015 Google announced they would be splitting Google+ into Photos & Streams. While, later Google announced the Google Photos standalone app which basically acts as a photo hosting service which can backup the photos stored on your phone for free.
Google+ Photos would eventually be shut down, and sure enough Google has Acknowledged that. According to a recent. According to a recent post by the official Google+ account, Google+ Photos will be shut down come 1st of August as Google makes the official transition to Google Photos. According to Google, the shutdown will affect Android users first, before it eventually ceases working for desktop and iOS users as well. “In an effort to ensure everyone has the best photos experience we can deliver, on August 1st we’ll start to shut down Google+ Photos — initially on Android, and soon thereafter on the Web and iOS.”
All your photos have already been migrated to the new Google Photos service. However if you don’t download or update to the Google Photos app, once Google+ Photos has been shut down, you won’t be able to access them until you get the latest app, which is currently available for free for both Android and iOS users.