Erlang/OTP 21 is a new major release with new features, improvements as well as incompatibilities.

Potential Incompatibilities

• All Corba applications are now moved from the OTP repository
• A new Corba repository will be created https://github.com/erlang
• New applications ftp and tftp, moved from inets
• ssl no longer supports 3_DES cipher suites or RSA-key exchange cipher suites by default
• Erlang:monitor on a primitive node (erl_interface, jinterface, etc) will no longer fail with badarg exception. Instead a monitor will be created, but it will only supervise the connection to the node.

Highlights Erts:

• Enhanced IO scalability
• Support for usage of distribution controller processes for alternative transports, routing etc
• compact instructions on 64bit systems for code below 4GB 20% less memory for loaded code
• Rewrite of the efile-driver with NIFs and "Dirty schedulers" resulting in faster file operations non-smp VM removed
• link and monitor optimized for scalability
• os:getenv/putenv now work on thread-safe emulation. No longer in sync with libc getenv(3). Manual synchronization will be needed.

Compiler:

• Misc compiler optimizations including contributions from the Elixir team resulting in 10% improvements in benchmarks
• "Tuple calls" have been removed from the run-time system.
• Code such as f({ok, Val}) -> {ok, Val} is now automatically rewritten to f({ok, Val} = Tuple) -> Tuple. this reduces code size, execution time, and removed GC pressure.
• More information in stacktrace from a number of operators
• erlang:get_stacktrace/0 deprecated to be replaced with try ... catch C:R:Stacktrace -> ...
• Creation of small maps with literal keys optimized.
• A new predefined macro OTP_RELEASE and preprocessor directives -if and -elif

Security:

• DTLS is now supported in the SSL application
• Enhanced support for distribution over TLS
• "unsecure" ciphers removed from defaults in SSL and SSH.
• A new option value defined to facilitate implementing exec servers. Old option kept for compatibility, but now gives errors on stderror.

Standard libraries:

• New API for logging, logger
• New uri_string module for parsing URIs according to "The standard"
• New function lists:search(list,fun/1) -> {ok, Value} | false
• Changed default behaviour of .erlang loading. escript, erlc, dialyzer and typer no longer load an .erlang at all.

For more details see http://erlang.org/download/otp_src_21.0.readme

Pre built versions for Windows can be fetched here: http://erlang.org/download/otp_win32_21.0.exe http://erlang.org/download/otp_win64_21.0.exe

Online documentation can be browsed here: http://erlang.org/documentation/doc-10.0/doc

Artifacts:

OTP-21.0.README file (131865 bytes)

otp_doc_html_21.0.tar.gz file (32501093 bytes)

otp_doc_man_21.0.tar.gz file (1311959 bytes)

otp_src_21.0.tar.gz file (84146631 bytes)

otp_win32_21.0.exe file (89473497 bytes)

otp_win64_21.0.exe file (91727413 bytes)