In Julia 0.7, readcsv(io[, T::Type]; opts...) was deprecated in favor of readdlm(io, ','[, T]; opts...). readdlm is in the DelimitedFiles standard library, so you’ll need a using DelimitedFiles
@tkoolen is correct; the DelimitedFiles standard library exports the readdlm function, which provides basic delimited file reading functionality. With the CSV.jl package, you can call CSV.read which provides many additional features/options for reading delimited files. You can call ?CSV.read from the repl to see documentation for the function, you can also check out the extensive examples section of the package documentation.