The latest long-term support branch is Mbed TLS 2.7.
IAR ARM 7.4 UPGRADE
All users of Mbed TLS 2.1 are advised to upgrade to a later version of Mbed TLS wherever possible. Mbed TLS 2.1 will not be supported after Autumn 2018. Mbed TLS 2.1.0 was first shipped on 4th September 2015, and is nearing the end of its life. Users of Mbed TLS 2.1 or any earlier version are recommended to upgrade to one of the maintained releases as Mbed TLS 2.1 is nearing its end-of-life.
IAR ARM 7.4 UPDATE
We recommend all users impacted by the bugs described above should update at an appropriate point in their development lifecycle. (2.11, 2.7, 2.1) Added support for TLS testing in out-of-source-tree builds using CMake. (2.11, 2.7, 2.1) Changed CMake defaults for IAR to treat all compiler warnings as errors. (2.11, 2.7, 2.1) Fixed redundant declaration of mbedtls_ssl_list_ciphersuites. (2.1) Added the macro MBEDTLS_X509_MAX_FILE_PATH_LEN that enables the user to configure the maximum length of a file path that can be buffered when calling mbedtls_x509_crt_parse_path(). (2.11, 2.7, 2.1) Fixed braces in mbedtls_memory_buffer_alloc_status(). (2.11, 2.7, 2.1) Fixed an issue with MicroBlaze support in bn_mul.h which was causing the build to fail. (2.11, 2.7, 2.1) Fixed compilation warnings with the IAR toolchain on 32-bit platforms. (2.11, 2.7, 2.1) Fixed the redefinition of _WIN32_WINNT, to avoid overriding a definition used by user applications. (2.11) Fixed the cert_write example to handle certificates signed with elliptic curves as well as RSA.
IAR ARM 7.4 CODE
Mbed TLS 2.7.4 and Mbed TLS 2.1.13 maintains binary and source code compatibility with their previous releases in the 2.7 and 2.1 branches. At this stage platform_util.h (and its associated platform_util.c) only contain mbedtls_platform_zeroize(), which is a critical function from a security point of view.