diff --git a/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c b/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
index 43bfc83e..9fb9919f 100644
--- a/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
+++ b/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
@@ -21,7 +21,7 @@
 #pragma GCC target("pclmul")
 #endif
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) || _MSC_VER < 1800
 #define __vectorcall
 #endif
 
diff --git a/src/libsodium/crypto_aead/aes256gcm/armcrypto/aead_aes256gcm_armcrypto.c b/src/libsodium/crypto_aead/aes256gcm/armcrypto/aead_aes256gcm_armcrypto.c
index 774d5d6c..898b4db9 100644
--- a/src/libsodium/crypto_aead/aes256gcm/armcrypto/aead_aes256gcm_armcrypto.c
+++ b/src/libsodium/crypto_aead/aes256gcm/armcrypto/aead_aes256gcm_armcrypto.c
@@ -15,7 +15,7 @@
 
 #if defined(HAVE_ARMCRYPTO) && defined(__clang__) && defined(NATIVE_LITTLE_ENDIAN)
 
-#ifndef _MSC_VER
+#if !defined(MSC_VER) || _MSC_VER < 1800
 #define __vectorcall
 #endif