Install 2D Animation 5.0 (or newer) from Package Manager
Important Note:
In the event that you had the 2D Animation 5.0 package installed before uninstalling the 2D IK package, you will encounter compilation errors. Uninstalling the 2D IK Package from the Package Manager will fix this.
There are certain cases where compilation errors may still exist even after uninstalling the 2D IK Package. To resolve this, you will need to restart the Unity Editor.
We expect all scenes and projects that utilise 2D IK to be upgradable in this way. Please let us know your questions or concerns in this thread.
I upgraded unity project to unity 2020.2.5 and then I notice my 2d animations stopped working which were done using ik and sprite skin, I logged the build and I came know that sprite skin script is missing on the object. but the animation works perfectly in editor. cannot find any solution.
I upgraded unity project firstly from 2019.2 to 2020.2.1 and then finally to 2020.2.5f
initially 2d animations were done using 2d ik preview version and it was working perfectly even in unity version 2020.2.1f, but when upgraded to 2020.2.5, animation only work in editor play mode and when we build for android these scripts get missing.
I have updated version of 2d animation which is 5.0.4.
@enzomedrano2011 2D IK is now a part of the 2D Animation package. Download the 2D Animation package for 2021.1 (2D Animation 6.0) and you should see all 2D IK components available.