This blog is updated daily.
A general description is here.
The built-in ‘HTTP’ server converted entire ‘Content-Type’ to lowercase including parameters which can cause issues for multi-part form boundaries (PR#16541).
‘data(package=*)’ is more careful in determining the path.
‘nchar(x, *)’ and ‘nzchar(x)’ gain a new argument ‘keepNA’ which governs how the result for ‘NA’s in ‘x’ is determined. For ‘nzchar()’ in general and ‘nchar()’ in the R 3.2.x series, the default remains ‘FALSE’ which is fully back compatible. From R 3.3.0, ‘nchar()’'s default will change to ‘keepNA = NA’ and you are advised to consider this for code portability.