.. include:: /../getting_started/vars.rst .. _section-Product-TLS-601: RTI TLS Support *************** OpenSSL upgrade =============== Release 6.0.1 of *TLS Support* uses OpenSSLĀ® 1.1.1d. (Release 5.3.1 used OpenSSL 1.0.2n, and Release 6.0.0 used OpenSSL 1.0.2o.) *TLS Support* 6.0.1 is API-compatible with OpenSSL versions 1.1.0a through 1.1.1d, not with versions earlier than OpenSSL 1.1.0a. .. note:: OpenSSL 1.0.2 will only be supported until the end of 2019 (https://www.openssl.org/policies/releasestrat.html), so it is recommended that you upgrade the version of OpenSSL that you are using to OpenSSL 1.1.1d for release 6.0.1. For instructions on installing the latest version of OpenSSL, see the :link_tls_install_guide_601:`RTI TLS Support Installation Guide 6.0.1<>`. Changes to building an application ================================== When building a Windows application, you must now link against **libssl** and **libcrypto** instead of **ssleay32** and **libeay32**. When building a Windows statically-linked application, you must now link against the system library **crypt32.lib**. When building a non-Windows statically-linked application, you may see this error: .. code-block:: bash undefined reference to 'pthread_atfork' If so, open your makefile and make sure that ``-lpthread`` (which is part of ``$(SYSLIBS)`` in the makefile generated by *RTI Code Generator*) appears after ``-lssl`` and ``-lcrypto``.