diff --git a/docs/3.0-migration-guide.d/combine_SSL_CID-TLS1_3_PADDING_GRANULARITY_options.md b/docs/3.0-migration-guide.d/combine_SSL_CID-TLS1_3_PADDING_GRANULARITY_options.md
new file mode 100644
index 0000000..405d572
--- /dev/null
+++ b/docs/3.0-migration-guide.d/combine_SSL_CID-TLS1_3_PADDING_GRANULARITY_options.md
@@ -0,0 +1,14 @@
+Combine the `MBEDTLS_SSL_CID_PADDING_GRANULARITY` and `MBEDTLS_SSL_TLS1_3_PADDING_GRANULARITY` options
+--
+
+This change affects users who modified the default `config.h` padding granularity
+settings, i.e. enabled at least one of the options.
+
+`config.h` options `MBEDTLS_SSL_CID_PADDING_GRANULARITY` and
+`MBEDTLS_SSL_TLS1_3_PADDING_GRANULARITY` were combined into one option because
+they used exactly the same padding mechanism and hence their respective padding
+granularities can be used in exactly the same way. This change simplifies the
+code maintenance.
+
+The new single option `MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY` can be used
+for both DTLS-CID and TLS 1.3.