Moving project to unity 2019.2 from 2019.1 UI not found errors after upgrade

I am getting several errors about UI stuff in my error log after upgrading my project.

"
Assets\Plugins\Pixel Crushers\Dialogue System\Scripts\UI Subsystem\Unity UI\Selector UI\UsableUnityUI.cs(39,28): error CS0234: The type or namespace name 'UI' does not exist in the namespace 'UnityEngine' (are you missing an assembly reference?)
"

"
Assets\Plugins\Pixel Crushers\Dialogue System\Scripts\Timeline\Playables\Bark\BarkClip.cs(7,19): error CS0234: The type or namespace name 'Timeline' does not exist in the namespace 'UnityEngine' (are you missing an assembly reference?)
"

and many more errors

 

apparently ui is in the package manager starting from that version

 

I already have the ui package installed