diff --git a/include/mbedtls/sha256.h b/include/mbedtls/sha256.h
index 2b98bee..6ef2245 100644
--- a/include/mbedtls/sha256.h
+++ b/include/mbedtls/sha256.h
@@ -103,6 +103,7 @@
  * \param ctx      The context to use. This must be initialized.
  * \param is224    This determines which function to use. This must be
  *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
+ *                 If #MBEDTLS_SHA256_NO_SHA224 is defined, this must be \c 0.
  *
  * \return         \c 0 on success.
  * \return         A negative error code on failure.
@@ -171,6 +172,7 @@
  * \param ctx      The context to use. This must be initialized.
  * \param is224    Determines which function to use. This must be
  *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
+ *                 If #MBEDTLS_SHA256_NO_SHA224 is defined, this must be \c 0.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256_starts( mbedtls_sha256_context *ctx,
                                                int is224 );
@@ -239,6 +241,7 @@
  *                 be a writable buffer of length \c 32 Bytes.
  * \param is224    Determines which function to use. This must be
  *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
+ *                 If #MBEDTLS_SHA256_NO_SHA224 is defined, this must be \c 0.
  */
 int mbedtls_sha256_ret( const unsigned char *input,
                         size_t ilen,
@@ -271,6 +274,7 @@
  *                 a writable buffer of length \c 32 Bytes.
  * \param is224    Determines which function to use. This must be either
  *                 \c 0 for SHA-256, or \c 1 for SHA-224.
+ *                 If #MBEDTLS_SHA256_NO_SHA224 is defined, this must be \c 0.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256( const unsigned char *input,
                                         size_t ilen,