diff --git a/lib/base/tlsutility.cpp b/lib/base/tlsutility.cpp
index e91f6cd18..29b5588be 100644
--- a/lib/base/tlsutility.cpp
+++ b/lib/base/tlsutility.cpp
@@ -244,7 +244,7 @@ void SetCipherListToSSLContext(const Shared<TlsContext>::Ptr& context, const Str
  * @param version String of a TLS version, for example "TLSv1.2".
  * @return The value of the corresponding TLS*_VERSION macro.
  */
-int ResolveTlsProtocolVersion(const std::string& version) {
+TlsProtocolMin ResolveTlsProtocolVersion(const std::string& version) {
 	if (version == "TLSv1.2") {
 		return TLS1_2_VERSION;
 	} else if (version == "TLSv1.3") {
diff --git a/lib/base/tlsutility.hpp b/lib/base/tlsutility.hpp
index 75f3815ca..90d15fb10 100644
--- a/lib/base/tlsutility.hpp
+++ b/lib/base/tlsutility.hpp
@@ -40,6 +40,8 @@ const auto RENEW_INTERVAL  = 60 * 60 * 24;
 
 typedef boost::asio::ssl::context TlsContext;
 
+typedef int TlsProtocolMin;
+
 void InitializeOpenSSL();
 
 String GetOpenSSLVersion();
@@ -48,7 +50,7 @@ void AddCRLToSSLContext(const Shared<TlsContext>::Ptr& context, const String& cr
 void AddCRLToSSLContext(X509_STORE *x509_store, const String& crlPath);
 void SetCipherListToSSLContext(const Shared<TlsContext>::Ptr& context, const String& cipherList);
 void SetTlsProtocolminToSSLContext(const Shared<TlsContext>::Ptr& context, const String& tlsProtocolmin);
-int ResolveTlsProtocolVersion(const std::string& version);
+TlsProtocolMin ResolveTlsProtocolVersion(const std::string& version);
 
 Shared<TlsContext>::Ptr SetupSslContext(const String& certPath = String(), const String& keyPath = String(), const String& caPath = String(),
 	const String& crlPath = String(), const String& cipherList = String(), const String& protocolmin = String(), DebugInfo di = {});