This page lists any changes in 2017.1 which might affect existing projects when you upgrade from earlier versions of Unity.
For example:
Changes in data format which may require re-baking.
Changes to the meaning or behavior of any existing functions, parameters or component values.
Deprecation of any function or feature. (Alternatives are suggested.)
UnityWebRequestTexture.GetTexture() nonReadable parameter change
This convenience API had a bug where nonReadable worked the opposite way then it should, that is setting it to true would result in a readable texture and vice versa. Now this has been corrected and parameter works the way it’s documented. Note, that if you create DownloadHandlerTexture directly, you are not affected.
Particle SystemA component that simulates fluid entities such as liquids, clouds and flames by generating and animating large numbers of small 2D images in the scene. More info
See in Glossary Stretched BillboardA textured 2D object that rotates so that it always faces the Camera. More info
See in Glossary Pivot parameter change
X axis pivots are now accurate on Stretched Billboards. You may need to reconfigure your pivot settings on affected projects.
Y axis pivots are also accurate now and Unity automatically reconfigures these pivots when you upgrade your project.
ShaderA program that runs on the GPU. More info
See in Glossary macro UNITY_APPLY_DITHER_CROSSFADE change
The macro was used for implementing the screendoor dithering effect for LODThe Level Of Detail (LOD) technique is an optimization that reduces the number of triangles that Unity has to render for a GameObject when its distance from the Camera increases. More info
See in Glossary cross-fading objects in the fragment shader. Previously you would need to pass the entire fragment IN structure to it. Now you only need to pass the screen position vector to it.
Remember that since 2017.1 the new dithercrossfade option is added for #pragma surface directive which can automatically generate the dithering code.
* 2018–04–12 Page amended