I have updated Krita to latest version and now can't render my simple animation with transparency.

I am trying to render one layer with animation frames, but I can't enable "store alpha channel" for some reason. It's locked.

I was trying also to add color layer and check "transparent color" but it doesn't help too.

Earlier I doesn't change settings at all, just hit "render".

What I am doing wrong?

When enable alpha channel is disabled, that means there is no transparency visible in your image. Can you see the transparency checkers at all?

Yep, I have transparency checker: