diff --git a/src/configwrapper.h b/src/configwrapper.h
index c22313d..326d1cd 100644
--- a/src/configwrapper.h
+++ b/src/configwrapper.h
@@ -21,7 +21,7 @@ class ConfigWrapper : public ConfigWrapperInterface
     CPP_DISABLE_COPY_MOVE(ConfigWrapper)
 
 public:
-    using value_t = typename std::conditional<std::is_same<T, std::string>::value, const T &, T>::type;
+    using value_t = std::conditional_t<std::is_same<T, std::string>::value, const T &, T>;
     using ConstraintCallback = ConfigConstraintReturnType(*)(value_t);
 
     ConfigWrapper() = default;
diff --git a/src/configwrapper_base.cpp b/src/configwrapper_base.cpp
index 0e2e619..f418a5d 100644
--- a/src/configwrapper_base.cpp
+++ b/src/configwrapper_base.cpp
@@ -10,6 +10,7 @@ INSTANTIATE_CONFIGWRAPPER_TEMPLATES(uint16_t)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(int16_t)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(uint32_t)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(int32_t)
+INSTANTIATE_CONFIGWRAPPER_TEMPLATES(int)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(uint64_t)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(int64_t)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(float)
diff --git a/src/configwrapper_optional.cpp b/src/configwrapper_optional.cpp
index ffa2d02..0ad5331 100644
--- a/src/configwrapper_optional.cpp
+++ b/src/configwrapper_optional.cpp
@@ -9,6 +9,8 @@ INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<int16_t>)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<uint16_t>)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<int32_t>)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<uint32_t>)
+INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<int>)
+INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<unsigned int>)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<int64_t>)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<uint64_t>)
 INSTANTIATE_CONFIGWRAPPER_TEMPLATES(std::optional<float>)