diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 17e6521..7adf103 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1753,6 +1753,9 @@
   }
 }
 
+void SSL_CTX_set_allow_unknown_alpn_protos(SSL_CTX *ctx, int enabled) {
+  ctx->allow_unknown_alpn_protos = !!enabled;
+}
 
 void SSL_CTX_set_tls_channel_id_enabled(SSL_CTX *ctx, int enabled) {
   ctx->tlsext_channel_id_enabled = !!enabled;