diff --git a/Makefile b/Makefile
index 0636d73..d3ab57e 100644
--- a/Makefile
+++ b/Makefile
@@ -48,6 +48,7 @@ install: check-dependencies
 	install -m 644 lib/resty/auto-ssl/storage_adapters/redis.lua $(INST_LUADIR)/resty/auto-ssl/storage_adapters/redis.lua
 	install -d $(INST_LUADIR)/resty/auto-ssl/utils
 	install -m 644 lib/resty/auto-ssl/utils/parse_openssl_time.lua $(INST_LUADIR)/resty/auto-ssl/utils/parse_openssl_time.lua
+	install -m 644 lib/resty/auto-ssl/utils/has_certificate.lua $(INST_LUADIR)/resty/auto-ssl/utils/has_certificate.lua
 	install -m 644 lib/resty/auto-ssl/utils/random_seed.lua $(INST_LUADIR)/resty/auto-ssl/utils/random_seed.lua
 	install -m 644 lib/resty/auto-ssl/utils/shell_execute.lua $(INST_LUADIR)/resty/auto-ssl/utils/shell_execute.lua
 	install -m 644 lib/resty/auto-ssl/utils/shuffle_table.lua $(INST_LUADIR)/resty/auto-ssl/utils/shuffle_table.lua