diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 51afb04..865e02c 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -81,7 +81,7 @@
  */
 
 /* We need to tell the compiler that we meant to leave out the null character. */
-static const char tls13_label_prefix[6] __attribute__ ((nonstring)) = "tls13 ";
+static const char tls13_label_prefix[6] MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING = "tls13 ";
 
 #define SSL_TLS1_3_KEY_SCHEDULE_HKDF_LABEL_LEN(label_len, context_len) \
     (2                     /* expansion length           */ \
diff --git a/library/ssl_tls13_keys.h b/library/ssl_tls13_keys.h
index f6d02b5..1509e9a 100644
--- a/library/ssl_tls13_keys.h
+++ b/library/ssl_tls13_keys.h
@@ -42,7 +42,7 @@
 
 /* We need to tell the compiler that we meant to leave out the null character. */
 #define MBEDTLS_SSL_TLS1_3_LABEL(name, string)       \
-    const unsigned char name    [sizeof(string) - 1] __attribute__ ((nonstring));
+    const unsigned char name    [sizeof(string) - 1] MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING;
 
 union mbedtls_ssl_tls13_labels_union {
     MBEDTLS_SSL_TLS1_3_LABEL_LIST
diff --git a/tests/psa-client-server/psasim/src/aut_psa_aead_encrypt_decrypt.c b/tests/psa-client-server/psasim/src/aut_psa_aead_encrypt_decrypt.c
index 83cd3c0..313397b 100644
--- a/tests/psa-client-server/psasim/src/aut_psa_aead_encrypt_decrypt.c
+++ b/tests/psa-client-server/psasim/src/aut_psa_aead_encrypt_decrypt.c
@@ -26,7 +26,8 @@
     uint8_t decrypt[BUFFER_SIZE] = { 0 };
     const uint8_t plaintext[] = "Hello World!";
     /* We need to tell the compiler that we meant to leave out the null character. */
-    const uint8_t key_bytes[32] __attribute__ ((nonstring)) = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
+    const uint8_t key_bytes[32] MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING =
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
     uint8_t nonce[PSA_AEAD_NONCE_LENGTH(PSA_KEY_TYPE_AES, PSA_ALG_CCM)];
     size_t nonce_length = sizeof(nonce);
     size_t ciphertext_length;
diff --git a/tests/psa-client-server/psasim/src/aut_psa_cipher_encrypt_decrypt.c b/tests/psa-client-server/psasim/src/aut_psa_cipher_encrypt_decrypt.c
index 22d0bfb..30b6982 100644
--- a/tests/psa-client-server/psasim/src/aut_psa_cipher_encrypt_decrypt.c
+++ b/tests/psa-client-server/psasim/src/aut_psa_cipher_encrypt_decrypt.c
@@ -26,7 +26,8 @@
     uint8_t encrypt[BUFFER_SIZE] = { 0 };
     uint8_t decrypt[BUFFER_SIZE] = { 0 };
     /* We need to tell the compiler that we meant to leave out the null character. */
-    const uint8_t key_bytes[32] __attribute__ ((nonstring)) = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
+    const uint8_t key_bytes[32] MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING =
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
     size_t encrypted_length;
     size_t decrypted_length;
 
diff --git a/tests/suites/test_suite_ssl_decrypt.function b/tests/suites/test_suite_ssl_decrypt.function
index 7282416..37265de 100644
--- a/tests/suites/test_suite_ssl_decrypt.function
+++ b/tests/suites/test_suite_ssl_decrypt.function
@@ -38,7 +38,7 @@
                               MBEDTLS_SSL_TRANSPORT_STREAM,
                               version);
     /* We need to tell the compiler that we meant to leave out the null character. */
-    const char sample_plaintext[3] __attribute__ ((nonstring)) = "ABC";
+    const char sample_plaintext[3] MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING = "ABC";
     mbedtls_ssl_context ssl;
     mbedtls_ssl_init(&ssl);
     uint8_t *buf = NULL;