Though package-specific minimum versions of R are given in the
Depends fields of individual
DESCRIPTION files, our general policy is to support the current version, the devel version, and four previous versions of R.
With the prerelease of R version 3.6.0 (Planting of a Tree) already available, and its final release slated for 2019-04-26, you can expect tidyverse packages to drop support for R 3.1 in the coming weeks. This aligns R version support in the tidyverse with RMarkdown, which as of the latest release requires R 3.2.3 (due to an update to the highr package).