Google started to roll out the Android P Developer Preview 5 (build number PPP5.180610.010) OTA update for first and second-generation Pixel smartphones. If you are already running the previous Developer Preview 4 (beta 3), you will get the OTA update on your device, other users can download and install the factory images manually.
DP5/Beta 4 is the release candidate build of Android P with near-final system behaviors and the official Android P APIs (API level 28).With the Beta 4 system images and updated build tools, app developers can test their apps with Android P. The Android P Developer Preview 5 OTA and factory images are available for Pixel, Pixel XL, Pixel 2 and Pixel 2XL devices. Other OEMs who are participating in the Android P Beta (OnePlus, Essential, Sony, Xioami, Nokia and Vivo) is expected to update their devices to Beta 4 over the coming weeks. Download Android P Beta 4 OTA/ Factory Images – Pixel – Factory Image — OTA – Pixel XL – Factory Image — OTA – Pixel 2 – Factory Image — OTA – Pixel 2 XL – Factory Image — OTA Installation Guide: After downloading the required file, you may follow this step-by-step guide to install the build on your device manually. Before you begin, you should take the necessary steps to ensure all your data is backed up. [Source]