diff --git a/library/x509_csr.c b/library/x509_csr.c
index bba9eaa..0a77bef 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -114,7 +114,7 @@
         /*
          * Detect supported extensions and skip unsupported extensions
          */
-        ret = mbedtls_oid_get_x509_ext_type(&extn_oid, &ext_type);
+        ret = mbedtls_x509_oid_get_x509_ext_type(&extn_oid, &ext_type);
 
         if (ret != 0) {
             /* Give the callback (if any) a chance to handle the extension */