The R core team announced today the release of R 3.4.1 (codename: Single Candle). This release fixes a few minor bugs reported after the release of R 3.4.0, including an issue sometimes encountered when attempting to install packages on Windows, and problems displaying functions including Unicode characters (like "日本語") in the Windows GUI. The other fixes are mostly relevant to packages developers and those building R from source, and you can see the full list in the announcement linked below.
At the time of writing, Windows builds are already available at the main CRAN cloud mirror, and the Debian builds are out, but Mac builds aren't there quite yet (unless you want to build from source). Binaries for all platforms should propagate across the mirror network over the next couple of days.
r-announce mailing list: R 3.4.1 is released