.. _section-index420:

*****************************
Upgrading from 4.1.0 to 4.2.0
*****************************

See :ref:`section-Install-Upgrade`, if you haven't already.

The following sections describe how to upgrade from |me| 4.1.0 to |me| 4.2.0.
They describe general, wire, and other compatibility issues between |me| 4.2.0
and previous releases.

.. attention::

  For important information on new and removed platforms and features in |me|
  4.2.0, see `Supported Platforms and Programming Languages
  <https://community.rti.com/static/documentation/connext-micro/4.2.0/doc/html/release/supported_platforms.html>`__
  and `What's New in 4.2.0
  <https://community.rti.com/static/documentation/connext-micro/4.2.0/doc/html/release/whats_new_420.html>`__
  in the |me| documentation.

See `RTI Connext Performance Benchmarks
<https://community.rti.com/static/documentation/performance/benchmarks/index.html>`__
for performance details in this release.

API Deprecation
---------------

|me| 4.2.0 is the last version to support the ability to specify a locator 
address (such as ``127.0.0.1``) without a transport name prefix. The next
version of |me| will no longer support this capability. For example, if you
register a transport with the name ``udp`` and for the address ``127.0.0.1``,
you must specify the locator as ``udp://127.0.0.1``.

To maintain compatibility with future |me| versions, we strongly suggest
updating your applications to specify the transport name prefix.

Library Compatibility
---------------------

In |me| 4.2.0, support for Extensible Types (XTypes) has been extracted from 
the core library ``rti_me`` into a new, separate library ``rti_me_ddsxtypes``. 
The XTypes module was integrated into ``rti_me`` in |me| 4.1.0. The functionality
remains unchanged.

By default, *rtiddsgen* will generate code that requires the ``rti_me_ddsxtypes``
library. However, if you pass ``-interpreted 0`` to *rtiddsgen* when generating
code, this library is not needed.

.. note::
  
  The CERT profile does not support the ``rti_me_ddsxtypes`` library. You must
  pass ``-interpreted 0`` to *rtiddsgen* when compiling IDL code for the CERT
  profile.

Refer to
`Link applications and libraries
<https://community.rti.com/static/documentation/connext-micro/4.2.0/doc/html/developing/prepare_development_environment.html#link-applications-and-libraries>`__
in the |me| documentation for information on linking your applications.

Transport Compatibility
-----------------------

Due to a fixed bug in |me| 4.2.0, the Zero Copy v2 transport is not backwards
compatible with applications using previous versions of |me| (4.1.0 and below).
Refer to `What’s Fixed in 4.2.0
<https://community.rti.com/static/documentation/connext-micro/4.2.0/doc/html/release/whats_fixed_420/whats_fixed_420_index.html>`__
for more information. To ensure compatibility, migrate other applications using
Zero Copy v2 to |me| 4.2.0.