Ruby 2.4 has optimized enumerable min max methods
CSV::Row#each etc. return enumerator when no block given
Ruby 2.4 DateTime#to_time & Time#to_time keeps info
Avoid exception for dup on Integer
Ruby 2.4 no exception for objects converted to IPAddr
Ruby 2.4 deprecated constants TRUE, FALSE & NIL
Ruby 2.4 allows custom suffix of rotated log files
Ruby 2.4 Hash#transform_values & destructive version
Binding irb - Runtime Invocation for IRB
Ruby 2.4 has added additional parameters for Logger#new
Ruby 2.4 has default basename for Tempfile#create
New arguments support for float & integer modifiers
Ruby 2.4 adds Enumerable#uniq & Enumerable::Lazy#uniq
Ruby 2.4 optimized lstrip & strip for ASCII strings
IO#readlines now accepts chomp flag as an argument
open-uri in Ruby 2.4 allows http to https redirection
Ruby 2.4 now has Dir.empty? and File.empty? methods
Ruby 2.4 Integer#digits extract digits in place-value
Ruby 2.4 adds compare by identity functionality
Ruby 2.4 MatchData#values_at
Ruby 2.4 adds infinite? and finite? methods to Numeric
Ruby 2.4 adds Comparable#clamp method
New liberal_parsing option for parsing bad CSV data
Enumerable#chunk not mandatory in Ruby 2.4
Ruby 2.4 unifies Fixnum and Bignum into Integer
Ruby 2.4 implements Array#min and Array#max
Ruby 2.4 Extracting captured data from Regexp results
Ruby 2.4 Regexp#match? not polluting global variables
Ruby 2.4 implements Enumerable#sum
String#concat, Array#concat & String#prepend Ruby 2.4
Hash#compact and Hash#compact! now part of Ruby 2.4