A reliable source is reporting that Google is very close to releasing its next major version of Android in the very near future.
Evan Blass claims Android 7.0 Nougat will be released in August with the security patch but it won't make its way to the Nexus 5.
Blass revelations can be believed to some extent since he has a great reputation of providing credible leaks before official release.
The preview 5 has integrated system images for Nexus including other popular devices, emulator for testing your app before uploading to Play Store.
Moreover, the preview also includes final APL(Application programming Interface ) level 24, system behaviors, new UI, bug fixes in addition to several optimizations across the system and in pre-installed apps.