Addition of change log and migration guide files.
Signed-off-by: TRodziewicz <tomasz.rodziewicz@mobica.com>
diff --git a/docs/3.0-migration-guide.d/rename_the__ret_functions.md b/docs/3.0-migration-guide.d/rename_the__ret_functions.md
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+Rename mbedtls_*_ret() cryptography functions whose deprecated variants have been removed in #4029
+--
+
+This change affects users who were using the `mbedtls_*_ret()` criptography functions.
+
+Those functions were created based on now-deprecated functions according to a
+requirement that a function needs to return a value. This change brings back the
+original names of those functions.
+
+To migrate to the this change the user can keep the `*_ret` names in their code
+and include the `compat_2.x.h` header file which holds macros with proper
+renaming or to rename those function in their code according to the list from
+mentioned header file.