diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4db200c..041b4ce 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,7 +30,7 @@ cmake_minimum_required(VERSION 3.1.0)
 project(monero-lws)
 
 enable_language(CXX)
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 option(BUILD_TESTS "Build Tests" OFF)
diff --git a/tests/unit/rest.test.cpp b/tests/unit/rest.test.cpp
index 8e421f4..1f17b04 100644
--- a/tests/unit/rest.test.cpp
+++ b/tests/unit/rest.test.cpp
@@ -27,7 +27,7 @@
 
 #include "framework.test.h"
 
-#include <optional>
+#include <boost/optional/optional.hpp>
 #include "db/data.h"
 #include "db/storage.test.h"
 #include "db/string.h"
@@ -111,7 +111,7 @@ LWS_CASE("rest_server")
 
   SETUP("Database and login")
   {
-    std::optional<lws::rest_server> server;
+    boost::optional<lws::rest_server> server;
     lws::db::test::cleanup_db on_scope_exit{};
     lws::db::storage db = lws::db::test::get_fresh_db();
     auto context =
diff --git a/tests/unit/wire/read.test.cpp b/tests/unit/wire/read.test.cpp
index 22bcf4e..c962669 100644
--- a/tests/unit/wire/read.test.cpp
+++ b/tests/unit/wire/read.test.cpp
@@ -47,7 +47,7 @@ namespace
     {
       EXPECT(Target(0) == wire::integer::cast_unsigned<Target>(std::uintmax_t(0)));
       EXPECT(limit::max() == wire::integer::cast_unsigned<Target>(std::uintmax_t(limit::max())));
-      if constexpr (limit::max() < max)
+      if (limit::max() < max)
       {
         EXPECT_THROWS_AS(wire::integer::cast_unsigned<Target>(std::uintmax_t(limit::max()) + 1), wire::exception);
         EXPECT_THROWS_AS(wire::integer::cast_unsigned<Target>(max), wire::exception);
@@ -68,7 +68,7 @@ namespace
 
     SETUP("intmax_t to " + boost::core::demangle(typeid(Target).name()))
     {
-      if constexpr (min < limit::min())
+      if (min < limit::min())
       {
         EXPECT_THROWS_AS(wire::integer::cast_signed<Target>(std::intmax_t(limit::min()) - 1), wire::exception);
         EXPECT_THROWS_AS(wire::integer::cast_signed<Target>(min), wire::exception);
@@ -76,7 +76,7 @@ namespace
       EXPECT(limit::min() == wire::integer::cast_signed<Target>(std::intmax_t(limit::min())));
       EXPECT(Target(0) == wire::integer::cast_signed<Target>(std::intmax_t(0)));
       EXPECT(limit::max() == wire::integer::cast_signed<Target>(std::intmax_t(limit::max())));
-      if constexpr (limit::max() < max)
+      if (limit::max() < max)
       {
         EXPECT_THROWS_AS(wire::integer::cast_signed<Target>(std::intmax_t(limit::max()) + 1), wire::exception);
         EXPECT_THROWS_AS(wire::integer::cast_signed<Target>(max), wire::exception);