The R core group announced today the release of R 3.3.3 (code-name: "Another Canoe"). As the wrap-up release of the R 3.3 series, this update mainly contains minor bug-fixes. (Bigger changes are planned for R 3.4.0, expected in mid-April.) Binaries for the Windows version are already up on the CRAN master site, and binaries for all platforms will appear on your local CRAN mirror within the next couple of days.
R 3.3.3 fixes an issue related to attempting to use download.file on sites that automatically redirect from http to https: now, R will re-attempt to download the secure link rather than failing. Other fixes include support for long vectors in the vapply function, the ability to use pmax (and pmin) on ordered factors, improved accuracy for qbeta for some extreme cases, corrected spelling for "Cincinnati" in the precip data set, and a few other minor issues.
R 3.3.3 should be completely compatible with your existing R 3.3.x scripts and data sets. Unless some major unforeseen bug rears its head between now and the release of R 3.4.0, this is the final release of the R 3.3 series, so it's definitely a good idea to upgrade when you can.
As always, thanks go to the R Core Group for the continued and welcome improvements to R!