diff --git a/src/_cffi_src/openssl/asn1.py b/src/_cffi_src/openssl/asn1.py
index fd8c5a4..8644d05 100644
--- a/src/_cffi_src/openssl/asn1.py
+++ b/src/_cffi_src/openssl/asn1.py
@@ -125,7 +125,6 @@
 int i2d_ASN1_INTEGER(ASN1_INTEGER *, unsigned char **);
 /* This is not a macro, but is const on some versions of OpenSSL */
 int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *, int);
-ASN1_TIME *M_ASN1_TIME_dup(void *);
 const ASN1_ITEM *ASN1_ITEM_ptr(ASN1_ITEM_EXP *);
 
 /* These aren't macros these arguments are all const X on openssl > 1.0.x */
@@ -159,10 +158,4 @@
 """
 
 CUSTOMIZATIONS = """
-/* This macro is removed in 1.1.0. We re-add it if required to support
-   pyOpenSSL versions older than whatever resolves
-   https://github.com/pyca/pyopenssl/issues/431 */
-#if !defined(M_ASN1_TIME_dup)
-#define M_ASN1_TIME_dup(a) (ASN1_TIME *)ASN1_STRING_dup((const ASN1_STRING *)a)
-#endif
 """