Dear OCaml users, 

The release of OCaml 4.13.0 is close. 

The set of new features has been stabilized, and core opam packages already 
work with this release (see [ http://check.ocamllabs.io/ | http://check.ocamllabs.io ] ). After two alpha releases, we 
have created a first beta version to help you update your softwares and libraries ahead of 
the release. 

If you find any bugs, please report them here: 

https://github.com/ocaml/ocaml/issues 

The full release of OCaml 4.13.0 is currently planned for September. 

Happy hacking, 
Florian Angeletti for the OCaml team. 

Installation instructions 
--------------------------------- 
The base compiler can be installed as an opam switch with the following commands 

opam update 
opam switch create 4.13.0~beta1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git 

If you want to tweak the configuration of the compiler, you can switch to the option variant with: 

opam update 
opam switch create <switch_name> --packages=ocaml-variants.4.13.0~beta1+options,<option_list> --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git 

where <option_list> is a comma separated list of ocaml-option-* packages. For instance, for a flambda and no-flat-float-array switch: 

opam switch create 4.13.0~beta1+flambda+nffa --packages=ocaml-variants.4.13.0~beta1+options,ocaml-option-flambda,ocaml-option-no-flat-float-array --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git 

All available options can be listed with "opam search ocaml-option". 

The source code for ths beta release is also available at these addresses: 

https://github.com/ocaml/ocaml/archive/4.13.0-beta1.tar.gz 
https://caml.inria.fr/pub/distrib/ocaml-4.13/ocaml-4.13.0~beta1.tar.gz 

-------------------------------------------------- 
Changes since the last alpha release 
-------------------------------------------------- 

- #10549: Stack overflow detection and naked pointers checking for ARM64 
(Xavier Leroy, review by Stephen Dolan) 

- #10442, #10446: Fix regression in the toplevel to #directory caused by 
corrections and improvements to the Load_path in #9611. #directory now 
adds the path to the start of the load path again (so files in the newly 
added directory take priority). 
(David Allsopp, report by Vasile Rotaru, review by Florian Angeletti 
and Nicolás Ojeda Bär) 

- #10450, #10558: keep %apply and %revapply primitives working with abstract 
types. This breach of backward compatibility was only present in the alpha 
releases of OCaml 4.13.0 . 
(Florian Angeletti, review by Thomas Refis and Leo White) 

- #10380: Correct handling of UTF-8 paths in configure on Windows 
(David Allsopp, review by Sébastien Hinderer) 

- #10543: Fix Ast_mapper to apply the mapping function to the constants in 
"interval" patterns `c1..c2`. 
(Guillaume Petiot, review by Gabriel Scherer and Nicolás Ojeda Bär) 

- #10550, #10551: fix pretty-print of gadt-pattern-with-type-vars 
(Chet Murthy, review by Gabriel Scherer) 

- #10497: Styling changes in the post-processed HTML manual (webman) 
(Wiktor Kuchta, review by Florian Angeletti)