Google seeded the fourth build of Android P for developers. Changes in Android P DP 4 (Beta 3) focused on fixing bugs from previous versions and optimization. Everything else in the update included a security patch in July of this year.
According to the blog post for developers, Android P Beta 3 as close as possible to what the user will have in the final release of the OS later this summer. In Google advise developers to «run in» versions of their apps for Android P on this build.
New test build is already available for smartphones Pixel first and second generation. Third-party device participating in the test will receive P Android Beta 3 soon. They include: Essential Phone, OnePlus 6, Nokia 7 Plus, Oppo R15 Pro Sony Xperia ZX2, Vivo X21/X21UD Mix and Xiaomi Mi 2S.