I am getting an error message I can't fix

I changed the editor from 2020.something to 2019.4.8f1 and I got this error I can’t fix: Library\PackageCache\com.unity.2d.common@4.0.0\Runtime\InternalBridge\InternalEngineBridge.cs(36,48): error CS0117: ‘SpriteRendererDataAccessExtensions’ does not contain a definition for ‘SetBatchDeformableBufferAndLocalAABBArray’

I am also getting a lot of “TexturePlatformSettings” errors. Please help me!

If someone comes across this, I was able to fix this error message by reinstalling all 2d packages in Package manager.

So you had a project set up in 2020x. Then downgraded it to 2019.4.8f1? And now you are getting a lots of errors? Sound exactly what Unity warns for when you try to downgrade a project. You really shoudn’t do that in most cases. I don’t know if there is some kind of fix, from what I know there isn’t next to just starting over in 2019.4.8f1 or going back to the original version.

Try Unity Collaborate from Package Manager, upgrade to lower version of Collaborate.

This might work.