We found two regressions. One on Active Record and one on Action Pack.
Took some time to fix those issues so the release was delayed until today.
Here are the changes from 4.0.1.rc3 to 4.0.1.rc4:
And the changes from 4.0.0 to 4.0.1:
If we don’t hit any more stumbling blocks, I’ll release 4.0.1 on
Friday, November 1st.