diff --git a/ChangeLog.d/semi-public-structure-fields.txt b/ChangeLog.d/semi-public-structure-fields.txt
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+++ b/ChangeLog.d/semi-public-structure-fields.txt
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+API changes
+   * Some fields of mbedtls_ssl_session and mbedtls_ssl_config are in a
+     different order. This only affects applications that define such
+     structures directly or serialize them.
+