Erlang/OTP 19.0-rc1 is available for testing.

This is the release candidate before the final OTP 19.0 product release in June 2016.

Between the 19.0 rc1 and the final release there will be new updates of
the master branch with corrections and minor new features.
Occasionally there might be new tags which we in that
case will communicate and ask you to test.

Erlang/OTP 19.0 is a new major release with new features, quite a few (characteristics) improvements, as well as a few incompatibilities.

See the Release Notes and the documentation for more details.

We would like to ask you to build and test this release candidate and send us
your feedback as soon as possible, so that we can make the necessary
corrections before OTP 19.0.

The release contains many changes; thus, some unexpected incompatibilities
or issues may have slipped through our tests.
Please try to build and run your current products/applications and let us
know about any problems.

Some highlights of the release are:

  • compiler, stdlib:
    • New preprocessor macros ?FUNCTION_NAME?FUNCTION_ARITY
    • New preprocessor directives -error(Term) and -warning(Term) to cause a compilation error or warning, respectively.
  • gen_statem a new state machine behavior
  • mnesia_ext: plugin of external storage solutions to mnesia
  • crypto: uses EVP interface in OpenSSL resulting in generally better performance and support for HW acceleration
  • ssh: performance improvements, uses the new gen_statem behavior
  • dialyzer: the support for maps is very much extended both the type specification syntax and the type analysis.
  • erts:
    • erlang:open_port(spawn, ...) 3-5 times faster
    • tracing, extensive improvements (scalability, speed, match specifications on send/receive, support for lttng, ...)
    • dirty schedulers improved
    • per process configurable handling of message_queue
    • fast loading of multiple modules
    • max_heap_size process flag
    • and much more ....

You can find the Release Notes with more detailed info at

You find the source code at in the official Erlang repository.

Git tag OTP-19.0-rc1

You can also read the documentation on-line here:
(see the Release Notes mentioned above for release notes which
are not updated in the doc, but the new functionality is)

We also want to thank all of you that have contributed with new features, bug-fixes, suggestions and bug reports.

The Erlang/OTP Team at Ericsson