diff --git a/CHANGELOG.md b/CHANGELOG.md
index 038a29fcd79..7a4430434ab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
     - NodeJS:
       - CHANGED: Use node-api instead of NAN. [#6452](https://github.com/Project-OSRM/osrm-backend/pull/6452)
     - Misc:
+      - FIXED: Partial fix migration from boost::optional to std::optional [#6551](https://github.com/Project-OSRM/osrm-backend/issues/6551), see also [#6592](https://github.com/Project-OSRM/osrm-backend/issues/6592)
       - CHANGED: keep libosrm* in the docker image for downstream linking [#6602](https://github.com/Project-OSRM/osrm-backend/pull/6602)
       - CHANGED: Move vector in CSVFilesParser instead copying it. [#6470](https://github.com/Project-OSRM/osrm-backend/pull/6470)
       - REMOVED: Get rid of unused functions in util/json_util.hpp. [#6446](https://github.com/Project-OSRM/osrm-backend/pull/6446)
@@ -22,6 +23,7 @@
       - FIXED: Typo in file name src/util/timed_historgram.cpp -> src/util/timed_histogram.cpp [#6428](https://github.com/Project-OSRM/osrm-backend/issues/6428)
       - CHANGED: Replace boost::string_ref with std::string_view [#6433](https://github.com/Project-OSRM/osrm-backend/pull/6433)
       - ADDED: Print tracebacks for Lua runtime errors [#6564](https://github.com/Project-OSRM/osrm-backend/pull/6564)
+      - FIXED: Added a variable to preprocessor guard in file osrm-backend/include/util/range_table.hpp to solve build error. [#6596](https://github.com/Project-OSRM/osrm-backend/pull/6596)
     - Routing:
       - FIXED: Fix adding traffic signal penalties during compression [#6419](https://github.com/Project-OSRM/osrm-backend/pull/6419)
 # 5.27.1
diff --git a/include/guidance/intersection_handler.hpp b/include/guidance/intersection_handler.hpp
index dcd62d4cbbe..2c922510bfd 100644
--- a/include/guidance/intersection_handler.hpp
+++ b/include/guidance/intersection_handler.hpp
@@ -15,11 +15,10 @@
 
 #include <algorithm>
 #include <cstddef>
+#include <optional>
 #include <utility>
 #include <vector>
 
-#include <boost/optional.hpp>
-
 namespace osrm::guidance
 {
 
@@ -129,7 +128,7 @@ class IntersectionHandler
     //     ^ via
     //
     // For this scenario returns intersection at `b` and `b`.
-    boost::optional<IntersectionHandler::IntersectionViewAndNode>
+    std::optional<IntersectionHandler::IntersectionViewAndNode>
     getNextIntersection(const NodeID at, const EdgeID via) const;
 
     bool isSameName(const EdgeID source_edge_id, const EdgeID target_edge_id) const;
diff --git a/include/guidance/sliproad_handler.hpp b/include/guidance/sliproad_handler.hpp
index a75f70a520c..533ac4dcfb2 100644
--- a/include/guidance/sliproad_handler.hpp
+++ b/include/guidance/sliproad_handler.hpp
@@ -9,10 +9,9 @@
 
 #include "util/node_based_graph.hpp"
 
+#include <optional>
 #include <vector>
 
-#include <boost/optional.hpp>
-
 namespace osrm::guidance
 {
 
@@ -43,9 +42,9 @@ class SliproadHandler final : public IntersectionHandler
                             Intersection intersection) const override final;
 
   private:
-    boost::optional<std::size_t> getObviousIndexWithSliproads(const EdgeID from,
-                                                              const Intersection &intersection,
-                                                              const NodeID at) const;
+    std::optional<std::size_t> getObviousIndexWithSliproads(const EdgeID from,
+                                                            const Intersection &intersection,
+                                                            const NodeID at) const;
 
     // Next intersection from `start` onto `onto` is too far away for a Siproad scenario
     bool nextIntersectionIsTooFarAway(const NodeID start, const EdgeID onto) const;
diff --git a/include/guidance/turn_handler.hpp b/include/guidance/turn_handler.hpp
index d3e25c79a19..6a52109925f 100644
--- a/include/guidance/turn_handler.hpp
+++ b/include/guidance/turn_handler.hpp
@@ -11,9 +11,8 @@
 #include "util/attributes.hpp"
 #include "util/node_based_graph.hpp"
 
-#include <boost/optional.hpp>
-
 #include <cstddef>
+#include <optional>
 #include <utility>
 #include <vector>
 
@@ -72,7 +71,7 @@ class TurnHandler final : public IntersectionHandler
 
     bool hasObvious(const EdgeID &via_edge, const Fork &fork) const;
 
-    boost::optional<Fork> findForkCandidatesByGeometry(Intersection &intersection) const;
+    std::optional<Fork> findForkCandidatesByGeometry(Intersection &intersection) const;
 
     bool isCompatibleByRoadClass(const Intersection &intersection, const Fork fork) const;
 
@@ -96,7 +95,7 @@ class TurnHandler final : public IntersectionHandler
     handleDistinctConflict(const EdgeID via_edge, ConnectedRoad &left, ConnectedRoad &right) const;
 
     // Classification
-    boost::optional<Fork> findFork(const EdgeID via_edge, Intersection &intersection) const;
+    std::optional<Fork> findFork(const EdgeID via_edge, Intersection &intersection) const;
 
     OSRM_ATTR_WARN_UNUSED
     Intersection assignLeftTurns(const EdgeID via_edge,
diff --git a/include/nodejs/node_osrm_support.hpp b/include/nodejs/node_osrm_support.hpp
index 5296dc4ed3b..4074d984e18 100644
--- a/include/nodejs/node_osrm_support.hpp
+++ b/include/nodejs/node_osrm_support.hpp
@@ -21,11 +21,11 @@
 #include <napi.h>
 
 #include <boost/assert.hpp>
-#include <boost/optional.hpp>
 
 #include <algorithm>
 #include <iostream>
 #include <iterator>
+#include <optional>
 #include <sstream>
 #include <stdexcept>
 #include <string>
@@ -345,11 +345,11 @@ inline engine_config_ptr argumentsToEngineConfig(const Napi::CallbackInfo &args)
     return engine_config;
 }
 
-inline boost::optional<std::vector<osrm::Coordinate>>
+inline std::optional<std::vector<osrm::Coordinate>>
 parseCoordinateArray(const Napi::Array &coordinates_array)
 {
     Napi::HandleScope scope(coordinates_array.Env());
-    boost::optional<std::vector<osrm::Coordinate>> resulting_coordinates;
+    std::optional<std::vector<osrm::Coordinate>> resulting_coordinates;
     std::vector<osrm::Coordinate> temp_coordinates;
 
     for (uint32_t i = 0; i < coordinates_array.Length(); ++i)
@@ -968,7 +968,7 @@ inline bool parseCommonParameters(const Napi::Object &obj, ParamType &params)
 
 inline PluginParameters argumentsToPluginParameters(
     const Napi::CallbackInfo &args,
-    const boost::optional<osrm::engine::api::BaseParameters::OutputFormatType> &output_format = {})
+    const std::optional<osrm::engine::api::BaseParameters::OutputFormatType> &output_format = {})
 {
     if (args.Length() < 3 || !args[1].IsObject())
     {
diff --git a/include/util/coordinate_calculation.hpp b/include/util/coordinate_calculation.hpp
index 4ebbafa5c52..53c803a1900 100644
--- a/include/util/coordinate_calculation.hpp
+++ b/include/util/coordinate_calculation.hpp
@@ -4,11 +4,11 @@
 #include "util/coordinate.hpp"
 
 #include <boost/math/constants/constants.hpp>
-#include <boost/optional.hpp>
 
 #include <algorithm>
 #include <cmath>
 #include <numeric>
+#include <optional>
 #include <utility>
 #include <vector>
 
@@ -102,9 +102,9 @@ double bearing(const Coordinate first_coordinate, const Coordinate second_coordi
 double computeAngle(const Coordinate first, const Coordinate second, const Coordinate third);
 
 // find the center of a circle through three coordinates
-boost::optional<Coordinate> circleCenter(const Coordinate first_coordinate,
-                                         const Coordinate second_coordinate,
-                                         const Coordinate third_coordinate);
+std::optional<Coordinate> circleCenter(const Coordinate first_coordinate,
+                                       const Coordinate second_coordinate,
+                                       const Coordinate third_coordinate);
 
 // find the radius of a circle through three coordinates
 double circleRadius(const Coordinate first_coordinate,
diff --git a/include/util/geojson_debug_policies.hpp b/include/util/geojson_debug_policies.hpp
index 3a209db0ac2..0f25badd0f4 100644
--- a/include/util/geojson_debug_policies.hpp
+++ b/include/util/geojson_debug_policies.hpp
@@ -1,6 +1,7 @@
 #ifndef OSRM_GEOJSON_DEBUG_POLICIES
 #define OSRM_GEOJSON_DEBUG_POLICIES
 
+#include <optional>
 #include <vector>
 
 #include "extractor/query_node.hpp"
@@ -9,8 +10,6 @@
 #include "util/node_based_graph.hpp"
 #include "util/typedefs.hpp"
 
-#include <boost/optional.hpp>
-
 namespace osrm::util
 {
 
@@ -20,7 +19,7 @@ struct NodeIdVectorToLineString
 
     // converts a vector of node ids into a linestring geojson feature
     util::json::Object operator()(const std::vector<NodeID> &node_ids,
-                                  const boost::optional<json::Object> &properties = {}) const;
+                                  const std::optional<json::Object> &properties = {}) const;
 
     const std::vector<util::Coordinate> &node_coordinates;
 };
@@ -29,7 +28,7 @@ struct CoordinateVectorToLineString
 {
     // converts a vector of node ids into a linestring geojson feature
     util::json::Object operator()(const std::vector<util::Coordinate> &coordinates,
-                                  const boost::optional<json::Object> &properties = {}) const;
+                                  const std::optional<json::Object> &properties = {}) const;
 };
 
 struct NodeIdVectorToMultiPoint
@@ -38,7 +37,7 @@ struct NodeIdVectorToMultiPoint
 
     // converts a vector of node ids into a linestring geojson feature
     util::json::Object operator()(const std::vector<NodeID> &node_ids,
-                                  const boost::optional<json::Object> &properties = {}) const;
+                                  const std::optional<json::Object> &properties = {}) const;
 
     const std::vector<util::Coordinate> &node_coordinates;
 };
@@ -47,7 +46,7 @@ struct CoordinateVectorToMultiPoint
 {
     // converts a vector of node ids into a linestring geojson feature
     util::json::Object operator()(const std::vector<util::Coordinate> &coordinates,
-                                  const boost::optional<json::Object> &properties = {}) const;
+                                  const std::optional<json::Object> &properties = {}) const;
 };
 
 } // namespace osrm::util
diff --git a/include/util/geojson_debug_policy_toolkit.hpp b/include/util/geojson_debug_policy_toolkit.hpp
index 62c1019ef1f..fcddc21a1a2 100644
--- a/include/util/geojson_debug_policy_toolkit.hpp
+++ b/include/util/geojson_debug_policy_toolkit.hpp
@@ -7,8 +7,7 @@
 
 #include <algorithm>
 #include <iterator>
-
-#include <boost/optional.hpp>
+#include <optional>
 
 namespace osrm::util
 {
@@ -84,7 +83,7 @@ struct NodeIdToCoordinate
 
 inline util::json::Object makeFeature(std::string type,
                                       util::json::Array coordinates,
-                                      const boost::optional<util::json::Object> &properties = {})
+                                      const std::optional<util::json::Object> &properties = {})
 {
     util::json::Object result;
     result.values["type"] = "Feature";
diff --git a/include/util/query_heap.hpp b/include/util/query_heap.hpp
index 463323efe87..f481a78f065 100644
--- a/include/util/query_heap.hpp
+++ b/include/util/query_heap.hpp
@@ -3,11 +3,11 @@
 
 #include <boost/assert.hpp>
 #include <boost/heap/d_ary_heap.hpp>
-#include <boost/optional.hpp>
 
 #include <algorithm>
 #include <limits>
 #include <map>
+#include <optional>
 #include <unordered_map>
 #include <vector>
 
@@ -289,26 +289,26 @@ class QueryHeap
         return inserted_nodes[index].node == node;
     }
 
-    boost::optional<HeapNode &> GetHeapNodeIfWasInserted(const NodeID node)
+    HeapNode *GetHeapNodeIfWasInserted(const NodeID node)
     {
         const auto index = node_index.peek_index(node);
         if (index >= static_cast<decltype(index)>(inserted_nodes.size()) ||
             inserted_nodes[index].node != node)
         {
-            return {};
+            return nullptr;
         }
-        return inserted_nodes[index];
+        return &inserted_nodes[index];
     }
 
-    boost::optional<const HeapNode &> GetHeapNodeIfWasInserted(const NodeID node) const
+    const HeapNode *GetHeapNodeIfWasInserted(const NodeID node) const
     {
         const auto index = node_index.peek_index(node);
         if (index >= static_cast<decltype(index)>(inserted_nodes.size()) ||
             inserted_nodes[index].node != node)
         {
-            return {};
+            return nullptr;
         }
-        return inserted_nodes[index];
+        return &inserted_nodes[index];
     }
 
     NodeID Min() const
diff --git a/include/util/range_table.hpp b/include/util/range_table.hpp
index 7bb6497c8c1..c5c978e0a8e 100644
--- a/include/util/range_table.hpp
+++ b/include/util/range_table.hpp
@@ -79,9 +79,9 @@ template <unsigned BLOCK_SIZE, storage::Ownership Ownership> class RangeTable
         unsigned last_length = 0;
         unsigned lengths_prefix_sum = 0;
         unsigned block_idx = 0;
-        unsigned block_counter = 0;
         BlockT block;
 #ifndef BOOST_ASSERT_IS_VOID
+        unsigned block_counter = 0;
         unsigned block_sum = 0;
 #endif
         for (const unsigned l : lengths)
@@ -109,7 +109,9 @@ template <unsigned BLOCK_SIZE, storage::Ownership Ownership> class RangeTable
             if (BLOCK_SIZE == block_idx)
             {
                 diff_blocks.push_back(block);
+#ifndef BOOST_ASSERT_IS_VOID
                 block_counter++;
+#endif
             }
 
             // we can only store strings with length 255
diff --git a/include/util/timezones.hpp b/include/util/timezones.hpp
index ff6b0bc988d..8105aaae47c 100644
--- a/include/util/timezones.hpp
+++ b/include/util/timezones.hpp
@@ -6,11 +6,11 @@
 #include <boost/filesystem/path.hpp>
 #include <boost/geometry.hpp>
 #include <boost/geometry/index/rtree.hpp>
-#include <boost/optional.hpp>
 
 #include <rapidjson/document.h>
 
 #include <chrono>
+#include <optional>
 
 namespace osrm::updater
 {
@@ -34,7 +34,7 @@ class Timezoner
     Timezoner(const char geojson[], std::time_t utc_time_now);
     Timezoner(const boost::filesystem::path &tz_shapes_filename, std::time_t utc_time_now);
 
-    boost::optional<struct tm> operator()(const point_t &point) const;
+    std::optional<struct tm> operator()(const point_t &point) const;
 
   private:
     void LoadLocalTimesRTree(rapidjson::Document &geojson, std::time_t utc_time);
diff --git a/src/guidance/intersection_handler.cpp b/src/guidance/intersection_handler.cpp
index 6cbd016a01f..197f280149c 100644
--- a/src/guidance/intersection_handler.cpp
+++ b/src/guidance/intersection_handler.cpp
@@ -426,7 +426,7 @@ void IntersectionHandler::assignTrivialTurns(const EdgeID via_eid,
         }
 }
 
-boost::optional<IntersectionHandler::IntersectionViewAndNode>
+std::optional<IntersectionHandler::IntersectionViewAndNode>
 IntersectionHandler::getNextIntersection(const NodeID at, const EdgeID via) const
 {
     // We use the intersection generator to jump over traffic signals, barriers. The intersection
@@ -449,7 +449,7 @@ IntersectionHandler::getNextIntersection(const NodeID at, const EdgeID via) cons
     if (intersection_parameters.node == SPECIAL_NODEID ||
         intersection_parameters.edge == SPECIAL_EDGEID)
     {
-        return boost::none;
+        return {};
     }
 
     auto intersection = extractor::intersection::getConnectedRoads<false>(node_based_graph,
@@ -464,11 +464,10 @@ IntersectionHandler::getNextIntersection(const NodeID at, const EdgeID via) cons
 
     if (intersection.size() <= 2 || intersection.isTrafficSignalOrBarrier())
     {
-        return boost::none;
+        return {};
     }
 
-    return boost::make_optional(
-        IntersectionViewAndNode{std::move(intersection), intersection_node});
+    return std::make_optional(IntersectionViewAndNode{std::move(intersection), intersection_node});
 }
 
 bool IntersectionHandler::isSameName(const EdgeID source_edge_id, const EdgeID target_edge_id) const
diff --git a/src/guidance/sliproad_handler.cpp b/src/guidance/sliproad_handler.cpp
index 702bdf59a38..0d0d6695e59 100644
--- a/src/guidance/sliproad_handler.cpp
+++ b/src/guidance/sliproad_handler.cpp
@@ -627,7 +627,7 @@ Intersection SliproadHandler::operator()(const NodeID /*nid*/,
 
 // Implementation details
 
-boost::optional<std::size_t> SliproadHandler::getObviousIndexWithSliproads(
+std::optional<std::size_t> SliproadHandler::getObviousIndexWithSliproads(
     const EdgeID from, const Intersection &intersection, const NodeID at) const
 {
     BOOST_ASSERT(from != SPECIAL_EDGEID);
@@ -638,14 +638,14 @@ boost::optional<std::size_t> SliproadHandler::getObviousIndexWithSliproads(
 
     if (index != 0)
     {
-        return boost::make_optional(index);
+        return std::make_optional(index);
     }
 
     // Otherwise check if the road is forking into two and one of them is a Sliproad;
     // then the non-Sliproad is the obvious one.
     if (intersection.size() != 3)
     {
-        return boost::none;
+        return {};
     }
 
     const auto forking = intersection[1].instruction.type == TurnType::Fork &&
@@ -653,7 +653,7 @@ boost::optional<std::size_t> SliproadHandler::getObviousIndexWithSliproads(
 
     if (!forking)
     {
-        return boost::none;
+        return {};
     }
 
     const auto first = getNextIntersection(at, intersection.getRightmostRoad().eid);
@@ -661,27 +661,27 @@ boost::optional<std::size_t> SliproadHandler::getObviousIndexWithSliproads(
 
     if (!first || !second)
     {
-        return boost::none;
+        return {};
     }
 
     if (first->intersection.isDeadEnd() || second->intersection.isDeadEnd())
     {
-        return boost::none;
+        return {};
     }
 
     // In case of loops at the end of the road, we will arrive back at the intersection
     // itself. If that is the case, the road is obviously not a sliproad.
     if (canBeTargetOfSliproad(first->intersection) && at != second->node)
     {
-        return boost::make_optional(std::size_t{2});
+        return std::make_optional(std::size_t{2});
     }
 
     if (canBeTargetOfSliproad(second->intersection) && at != first->node)
     {
-        return boost::make_optional(std::size_t{1});
+        return std::make_optional(std::size_t{1});
     }
 
-    return boost::none;
+    return {};
 }
 
 bool SliproadHandler::nextIntersectionIsTooFarAway(const NodeID start, const EdgeID onto) const
diff --git a/src/guidance/turn_handler.cpp b/src/guidance/turn_handler.cpp
index b13cbf1c927..10038ba21b3 100644
--- a/src/guidance/turn_handler.cpp
+++ b/src/guidance/turn_handler.cpp
@@ -6,10 +6,10 @@
 
 #include <algorithm>
 #include <limits>
+#include <optional>
 #include <utility>
 
 #include <boost/assert.hpp>
-#include <boost/optional.hpp>
 
 using osrm::util::angularDeviation;
 
@@ -585,7 +585,7 @@ Intersection TurnHandler::assignRightTurns(const EdgeID via_edge,
 }
 
 // finds a fork candidate by just looking at the geometry and angle of an intersection
-boost::optional<TurnHandler::Fork>
+std::optional<TurnHandler::Fork>
 TurnHandler::findForkCandidatesByGeometry(Intersection &intersection) const
 {
     if (intersection.size() >= 3)
@@ -642,7 +642,7 @@ TurnHandler::findForkCandidatesByGeometry(Intersection &intersection) const
             }
         }
     }
-    return boost::none;
+    return {};
 }
 
 // check if the fork candidates (all roads between left and right) and the
@@ -678,8 +678,8 @@ bool TurnHandler::isCompatibleByRoadClass(const Intersection &intersection, cons
 
 // Checks whether a three-way-intersection coming from `via_edge` is a fork
 // with `intersection` as described as in #IntersectionExplanation@intersection_handler.hpp
-boost::optional<TurnHandler::Fork> TurnHandler::findFork(const EdgeID via_edge,
-                                                         Intersection &intersection) const
+std::optional<TurnHandler::Fork> TurnHandler::findFork(const EdgeID via_edge,
+                                                       Intersection &intersection) const
 {
     auto fork = findForkCandidatesByGeometry(intersection);
     if (fork)
@@ -720,7 +720,7 @@ boost::optional<TurnHandler::Fork> TurnHandler::findFork(const EdgeID via_edge,
         }
     }
 
-    return boost::none;
+    return {};
 }
 
 void TurnHandler::handleDistinctConflict(const EdgeID via_edge,
diff --git a/src/util/coordinate_calculation.cpp b/src/util/coordinate_calculation.cpp
index 3bc17266448..4686a9827d0 100644
--- a/src/util/coordinate_calculation.cpp
+++ b/src/util/coordinate_calculation.cpp
@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <iterator>
 #include <limits>
+#include <optional>
 #include <utility>
 
 namespace osrm::util::coordinate_calculation
@@ -173,14 +174,14 @@ double computeAngle(const Coordinate first, const Coordinate second, const Coord
     return angle;
 }
 
-boost::optional<Coordinate>
+std::optional<Coordinate>
 circleCenter(const Coordinate C1, const Coordinate C2, const Coordinate C3)
 {
     // free after http://paulbourke.net/geometry/circlesphere/
     // require three distinct points
     if (C1 == C2 || C2 == C3 || C1 == C3)
     {
-        return boost::none;
+        return {};
     }
 
     // define line through c1, c2 and c2,c3
@@ -195,7 +196,7 @@ circleCenter(const Coordinate C1, const Coordinate C2, const Coordinate C3)
         (std::abs(C2C1_lat) < std::numeric_limits<double>::epsilon() &&
          std::abs(C3C2_lat) < std::numeric_limits<double>::epsilon()))
     {
-        return boost::none;
+        return {};
     }
     else if (std::abs(C2C1_lon) < std::numeric_limits<double>::epsilon())
     {
@@ -233,7 +234,7 @@ circleCenter(const Coordinate C1, const Coordinate C2, const Coordinate C3)
 
         // can this ever happen?
         if (std::abs(C2C1_slope - C3C2_slope) < std::numeric_limits<double>::epsilon())
-            return boost::none;
+            return {};
 
         const double C1_y = static_cast<double>(toFloating(C1.lat));
         const double C1_x = static_cast<double>(toFloating(C1.lon));
@@ -247,7 +248,7 @@ circleCenter(const Coordinate C1, const Coordinate C2, const Coordinate C3)
                            (2 * (C3C2_slope - C2C1_slope));
         const double lat = (0.5 * (C1_x + C2_x) - lon) / C2C1_slope + 0.5 * (C1_y + C2_y);
         if (lon < -180.0 || lon > 180.0 || lat < -90.0 || lat > 90.0)
-            return boost::none;
+            return {};
         else
             return Coordinate(FloatLongitude{lon}, FloatLatitude{lat});
     }
diff --git a/src/util/geojson_debug_policies.cpp b/src/util/geojson_debug_policies.cpp
index afdba87ab5c..9fd2ad60dba 100644
--- a/src/util/geojson_debug_policies.cpp
+++ b/src/util/geojson_debug_policies.cpp
@@ -17,7 +17,7 @@ NodeIdVectorToLineString::NodeIdVectorToLineString(
 // converts a vector of node ids into a linestring geojson feature
 util::json::Object
 NodeIdVectorToLineString::operator()(const std::vector<NodeID> &node_ids,
-                                     const boost::optional<json::Object> &properties) const
+                                     const std::optional<json::Object> &properties) const
 {
     util::json::Array coordinates;
     std::transform(node_ids.begin(),
@@ -37,7 +37,7 @@ NodeIdVectorToMultiPoint::NodeIdVectorToMultiPoint(
 
 util::json::Object
 NodeIdVectorToMultiPoint::operator()(const std::vector<NodeID> &node_ids,
-                                     const boost::optional<json::Object> &properties) const
+                                     const std::optional<json::Object> &properties) const
 {
     util::json::Array coordinates;
     std::transform(node_ids.begin(),
@@ -51,7 +51,7 @@ NodeIdVectorToMultiPoint::operator()(const std::vector<NodeID> &node_ids,
 //----------------------------------------------------------------
 util::json::Object
 CoordinateVectorToMultiPoint::operator()(const std::vector<util::Coordinate> &input_coordinates,
-                                         const boost::optional<json::Object> &properties) const
+                                         const std::optional<json::Object> &properties) const
 {
     auto coordinates = makeJsonArray(input_coordinates);
     return makeFeature("MultiPoint", std::move(coordinates), properties);
@@ -60,7 +60,7 @@ CoordinateVectorToMultiPoint::operator()(const std::vector<util::Coordinate> &in
 //----------------------------------------------------------------
 util::json::Object
 CoordinateVectorToLineString::operator()(const std::vector<util::Coordinate> &input_coordinates,
-                                         const boost::optional<json::Object> &properties) const
+                                         const std::optional<json::Object> &properties) const
 {
     auto coordinates = makeJsonArray(input_coordinates);
     return makeFeature("LineString", std::move(coordinates), properties);
diff --git a/src/util/timezones.cpp b/src/util/timezones.cpp
index 179e2d11ae3..f11b1860a4e 100644
--- a/src/util/timezones.cpp
+++ b/src/util/timezones.cpp
@@ -5,13 +5,13 @@
 
 #include <boost/filesystem/fstream.hpp>
 #include <boost/filesystem/path.hpp>
-#include <boost/optional.hpp>
 
 #include <rapidjson/document.h>
 #include <rapidjson/error/en.h>
 #include <rapidjson/istreamwrapper.h>
 
 #include <fstream>
+#include <optional>
 #include <regex>
 #include <string>
 #include <unordered_map>
@@ -157,7 +157,7 @@ void Timezoner::LoadLocalTimesRTree(rapidjson::Document &geojson, std::time_t ut
     rtree = rtree_t(polygons);
 }
 
-boost::optional<struct tm> Timezoner::operator()(const point_t &point) const
+std::optional<struct tm> Timezoner::operator()(const point_t &point) const
 {
     std::vector<rtree_t::value_type> result;
     rtree.query(boost::geometry::index::intersects(point), std::back_inserter(result));
@@ -167,6 +167,6 @@ boost::optional<struct tm> Timezoner::operator()(const point_t &point) const
         if (boost::geometry::within(point, local_times[index].first))
             return local_times[index].second;
     }
-    return boost::none;
+    return {};
 }
 } // namespace osrm::updater