The P20 ships with Android 8.1 "Oreo" with Huawei's EMUI interface and software suite. In December 2018, Huawei began to roll out an upgrade to Android 9.0 "Pie" with EMUI 9.0, adding features such as screen gesture-based navigation, Digital Balance (a dashboard for tracking and limiting device usage), HiVision (an augmented reality object recognition experience for the camera), and Password Vault among other features.
Method to recover messages from huawei p20
Android Data Recovery is a good way for you to choose. It can recover lots of lost data including messages and Videos. More importantly, with a click, you can not only regain WhatsApp, but also recover contacts, text messages, photos, music and video.
More info;Recover contacts from android