Previously in 5.5 unity would not import custom frames per second(FPS) values such as 28FPS, instead it would change the fps to 12.5FPS and then scale the frames to match.
In 5.6 it will now import the custom FPS vales.
5.6 behavior is clearly the correct one but has broken my old animations with custom FPS. Can someone confirm this is going to stay and I should put time into fixing these broken anims?
I would really appreciate confirmation about what Unity is doing going forward with this.
I just wanted to note this behavior is new between b5 and b6, although I had to revert back to b5 due to other bugs in b6
Hello!
Yes, this is a bug I’ve fixed, it is going to stay, as the previous behavior was not at all expected 
This is the issue: Unity Issue Tracker - The sample rate of animation imported to Unity is set 12.5fps if lower than certain number
Cheers!
Great, thank you for letting me know!
Would be nice if there was a way to auto update the end frame as lots of my anims are broken and it’s time consuming working out what the correct settings should be (they should just how the default was on import)
I’m not sure I understand what you mean by that 
Sorry I missed your reply, I meant previously if you had a fbx with custom fps it would default to 12.5fps and change the end frame to get the anim speed correct. Now with the fixed fps the old custom fps anims get the correct NEW fps but keep the OLD end frame so it leaves dead space or cuts off frames at the end of the animation.
I had to go though and reset all my anim lengths which was annoying, its fine for me now but could be automatic for other users in the future.