The source packages sp 1.4-4 and rgdal 1.5-17 are now on CRAN (thanks to
the CRAN team). They are probably the last releases prior to turning off
by default intrusive warnings intended to alert users and package
maintainers to the major changes that have occurred to switch CRS
representation from Proj4 to WKT2 (2019) strings. If you notice unexpected
behaviour, please respond here or by email or ping @rsbivand on github if
your package uses it; twitter @RogerBivand is also possible, but not good
for longer messages.