More removals found in changelog entries
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/docs/4.0-migration-guide/configuration.md b/docs/4.0-migration-guide/configuration.md
index 0065de4..c8e54f6 100644
--- a/docs/4.0-migration-guide/configuration.md
+++ b/docs/4.0-migration-guide/configuration.md
@@ -32,3 +32,13 @@
### Removal of `check_config.h`
The header `mbedtls/check_config.h` is no longer present. Including it from user configuration files was already obsolete in Mbed TLS 3.x, since it enforces properties the configuration as adjusted by `mbedtls/build_info.h`, not properties that the user configuration is expected to meet.
+
+### Changes to TLS options
+
+#### Enabling null cipher suites
+
+The option to enable null cipher suites in TLS 1.2 has been renamed from `MBEDTLS_CIPHER_NULL_CIPHER` to `MBEDTLS_SSL_NULL_CIPHERSUITES`. It remains disabled in the default configuration.
+
+#### Removal of backward compatibility options
+
+The option `MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT` has been removed. Only the version standardized in RFC 9146 is supported now.