Julia v1.3 Release Notes

New language features

  • Support for Unicode 12.1.0 (#32002).
  • Methods can now be added to an abstract type (#31916).

Language changes

Multi-threading changes

Build system changes

New library functions

  • findfirst, findlast, findnext and findprev now accept a character as first argument to search for that character in a string passed as the second argument (#31664).
  • New findall(pattern, string) method where pattern is a string or regex (#31834).

Standard library changes

  • Regex can now be multiplied (*) and exponentiated (^), like strings (#23422).
  • Cmd interpolation ($`$(x::Cmd) a b c`$ where) now propagates x's process flags (environment, flags, working directory, etc) if x is the first interpolant and errors otherwise (#24353).
  • IPAddr subtypes now behave like scalars when used in broadcasting (#32133).
  • clamp can now handle missing values (#31066).


  • dlopen() can now be invoked in do-block syntax, similar to open().


  • The BLAS submodule no longer exports dot, which conflicts with that in LinearAlgebra (#31838).
  • diagm and spdiagm now accept optional m,n initial arguments to specify a size (#31654).
  • Hessenberg factorizations H now support efficient shifted solves (H+µI) \ b and determinants, and use a specialized tridiagonal factorization for Hermitian matrices. There is also a new UpperHessenberg matrix type (#31853).



  • DateTime and Time formatting/parsing now supports 12-hour clocks with AM/PM via I and p codes, similar to strftime (#32308).
  • Fixed repr such that it displays Time as it would be entered in Julia (#32103).


  • getipaddrs returns IP addresses in the order provided by libuv (#32260).
  • getipaddr prefers to return the first IPv4 interface address provided by libuv (#32260).


  • mean now accepts both a function argument and a dims keyword (#31576).


  • foldr and mapfoldr now work on any iterator that supports Iterators.reverse, not just arrays (#31781).

External dependencies

Tooling Improvements

  • The ClangSA.jl static analysis package has been imported, which makes use of the clang static analyzer to validate GC invariants in Julia's C code. The analysis may be run using make -C src analyzegc.