diff --git a/library/x509_crl.c b/library/x509_crl.c
index edeb39b..4c898c9 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -614,6 +614,7 @@
 }
 #endif /* MBEDTLS_FS_IO */
 
+#if defined(MBEDTLS_X509_INFO)
 /*
  * Return an informational string about the certificate.
  */
@@ -693,6 +694,7 @@
 
     return( (int) ( size - n ) );
 }
+#endif /* MBEDTLS_X509_INFO */
 
 /*
  * Initialize a CRL chain