error CS0234: The type or namespace name 'Daydream' does not exist in the namespace 'UnityEditor.XR'

I just updated my unity version from 2019.1.6 to 2020.2.6. Now I am getting these errors and I have lost some of my prefabs. Can anyone help me to solve this. (I am currently working on VR project)

Daydream support was removed in 2020.1. Google released an open source cardboard plugin for 2020.1+ which they recommend using as a replacement: Hướng dẫn nhanh về Google Cardboard dành cho Unity  |  Google for Developers

See google’s suggestions here: Quickstart for Google VR SDK for Unity with Android  |  Google for Developers

Ok, But I need use gvr editor emulator, What can I do?

Too late reply…You need to downgrade version maybe Unity 2018.x.xx

Is there any way to continue using daydream externally? add it optionally in Unity? Discontinuing this plugin was one of the worst decisions google made, you search the internet for tutorials and you can’t find any google cardboard with Unity 2020 or 2021, Unity’s own documentation with the EscapeRoom tutorial does not provide for the use of this Cardboard API that is the most popular, this is terrible, now to perform the tests and emulate it has become impossible and you have to keep generating an APK to test. When using Gvr, it already had a stereoscopic lens emulator and you could emulate the movements by holding ALT. This is regrettable and a big setback in my opinion, both from a product standpoint and productivity to develop, plus there is not documentation from Unity for Google Cardboard, itself and the change of architecture to XR has added a totally unnecessary complexity to a project.

Unity now only supporting Oculus and OpenXR, Google Carboard being the most popular in the world, I can’t understand that.