diff --git a/gtsam/discrete/DiscreteFactorGraph.h b/gtsam/discrete/DiscreteFactorGraph.h
index 3fbb64d50..8b30cb963 100644
--- a/gtsam/discrete/DiscreteFactorGraph.h
+++ b/gtsam/discrete/DiscreteFactorGraph.h
@@ -155,7 +155,7 @@ class GTSAM_EXPORT DiscreteFactorGraph
    * @return DiscreteBayesNet encoding posterior P(X|Z)
    */
   DiscreteBayesNet sumProduct(
-      OptionalOrderingType orderingType = boost::none) const;
+      OptionalOrderingType orderingType = {}) const;
 
   /**
    * @brief Implement the sum-product algorithm
@@ -172,7 +172,7 @@ class GTSAM_EXPORT DiscreteFactorGraph
    * @return DiscreteLookupDAG DAG with lookup tables
    */
   DiscreteLookupDAG maxProduct(
-      OptionalOrderingType orderingType = boost::none) const;
+      OptionalOrderingType orderingType = {}) const;
 
   /**
    * @brief Implement the max-product algorithm
@@ -189,7 +189,7 @@ class GTSAM_EXPORT DiscreteFactorGraph
    * @return DiscreteValues : MPE
    */
   DiscreteValues optimize(
-      OptionalOrderingType orderingType = boost::none) const;
+      OptionalOrderingType orderingType = {}) const;
 
   /**
    * @brief Find the maximum probable explanation (MPE) by doing max-product.
diff --git a/gtsam/inference/BayesTree-inst.h b/gtsam/inference/BayesTree-inst.h
index 055971a82..65ba37889 100644
--- a/gtsam/inference/BayesTree-inst.h
+++ b/gtsam/inference/BayesTree-inst.h
@@ -25,7 +25,6 @@
 #include <gtsam/base/treeTraversal-inst.h>
 #include <gtsam/base/timing.h>
 
-#include <boost/optional.hpp>
 #include <fstream>
 
 namespace gtsam {
diff --git a/gtsam/inference/BayesTreeCliqueBase-inst.h b/gtsam/inference/BayesTreeCliqueBase-inst.h
index 6da7d0fe4..37ed49055 100644
--- a/gtsam/inference/BayesTreeCliqueBase-inst.h
+++ b/gtsam/inference/BayesTreeCliqueBase-inst.h
@@ -178,7 +178,7 @@ namespace gtsam {
                            this->conditional()->endParents());
         auto separatorMarginal =
             p_Cp.marginalMultifrontalBayesNet(Ordering(indicesS), function);
-        cachedSeparatorMarginal_.reset(*separatorMarginal);
+        cachedSeparatorMarginal_ = *separatorMarginal;
       }
     }
 
@@ -217,7 +217,7 @@ namespace gtsam {
       }
 
       //Delete CachedShortcut for this clique
-      cachedSeparatorMarginal_ = boost::none;
+      cachedSeparatorMarginal_ = {};
     }
 
   }
diff --git a/gtsam/inference/BayesTreeCliqueBase.h b/gtsam/inference/BayesTreeCliqueBase.h
index c9bb6db94..4cb0941b9 100644
--- a/gtsam/inference/BayesTreeCliqueBase.h
+++ b/gtsam/inference/BayesTreeCliqueBase.h
@@ -21,10 +21,10 @@
 #include <gtsam/inference/Ordering.h>
 #include <gtsam/base/types.h>
 #include <gtsam/base/FastVector.h>
-#include <boost/optional.hpp>
 
 #include <string>
 #include <mutex>
+#include <optional>
 
 namespace gtsam {
 
@@ -102,7 +102,7 @@ namespace gtsam {
     /// @}
 
     /// This stores the Cached separator marginal P(S)
-    mutable boost::optional<FactorGraphType> cachedSeparatorMarginal_;
+    mutable std::optional<FactorGraphType> cachedSeparatorMarginal_;
     /// This protects Cached seperator marginal P(S) from concurrent read/writes
     /// as many the functions which access it are const (hence the mutable)
     /// leading to the false impression that these const functions are thread-safe
@@ -174,7 +174,7 @@ namespace gtsam {
      */
     void deleteCachedShortcuts();
 
-    const boost::optional<FactorGraphType>& cachedSeparatorMarginal() const {
+    const std::optional<FactorGraphType>& cachedSeparatorMarginal() const {
       std::lock_guard<std::mutex> marginalLock(cachedSeparatorMarginalMutex_);
       return cachedSeparatorMarginal_; 
     }
@@ -194,7 +194,7 @@ namespace gtsam {
     /** Non-recursive delete cached shortcuts and marginals - internal only. */
     void deleteCachedShortcutsNonRecursive() { 
       std::lock_guard<std::mutex> marginalLock(cachedSeparatorMarginalMutex_);
-      cachedSeparatorMarginal_ = boost::none; 
+      cachedSeparatorMarginal_ = {}; 
     }
 
   private:
diff --git a/gtsam/inference/DotWriter.cpp b/gtsam/inference/DotWriter.cpp
index eac0c90f9..8047c281f 100644
--- a/gtsam/inference/DotWriter.cpp
+++ b/gtsam/inference/DotWriter.cpp
@@ -40,7 +40,7 @@ void DotWriter::digraphPreamble(ostream* os) const {
 }
 
 void DotWriter::drawVariable(Key key, const KeyFormatter& keyFormatter,
-                             const boost::optional<Vector2>& position,
+                             const std::optional<Vector2>& position,
                              ostream* os) const {
   // Label the node with the label from the KeyFormatter
   *os << "  var" << key << "[label=\"" << keyFormatter(key)
@@ -54,7 +54,7 @@ void DotWriter::drawVariable(Key key, const KeyFormatter& keyFormatter,
   *os << "];\n";
 }
 
-void DotWriter::DrawFactor(size_t i, const boost::optional<Vector2>& position,
+void DotWriter::DrawFactor(size_t i, const std::optional<Vector2>& position,
                            ostream* os) {
   *os << "  factor" << i << "[label=\"\", shape=point";
   if (position) {
@@ -76,26 +76,28 @@ static void ConnectVariableFactor(Key key, const KeyFormatter& keyFormatter,
 }
 
 /// Return variable position or none
-boost::optional<Vector2> DotWriter::variablePos(Key key) const {
-  boost::optional<Vector2> result = boost::none;
+std::optional<Vector2> DotWriter::variablePos(Key key) const {
+  std::optional<Vector2> result = {};
 
   // Check position hint
   Symbol symbol(key);
   auto hint = positionHints.find(symbol.chr());
-  if (hint != positionHints.end())
-    result.reset(Vector2(symbol.index(), hint->second));
+  if (hint != positionHints.end()) {
+    result = Vector2(symbol.index(), hint->second);
+  }
 
   // Override with explicit position, if given.
   auto pos = variablePositions.find(key);
-  if (pos != variablePositions.end())
-    result.reset(pos->second);
+  if (pos != variablePositions.end()) {
+    result = pos->second;
+  }
 
   return result;
 }
 
 void DotWriter::processFactor(size_t i, const KeyVector& keys,
                               const KeyFormatter& keyFormatter,
-                              const boost::optional<Vector2>& position,
+                              const std::optional<Vector2>& position,
                               ostream* os) const {
   if (plotFactorPoints) {
     if (binaryEdges && keys.size() == 2) {
diff --git a/gtsam/inference/DotWriter.h b/gtsam/inference/DotWriter.h
index 4973f0e53..ff20f5fa0 100644
--- a/gtsam/inference/DotWriter.h
+++ b/gtsam/inference/DotWriter.h
@@ -25,6 +25,7 @@
 #include <iosfwd>
 #include <map>
 #include <set>
+#include <optional>
 
 namespace gtsam {
 
@@ -80,20 +81,20 @@ struct GTSAM_EXPORT DotWriter {
 
   /// Create a variable dot fragment.
   void drawVariable(Key key, const KeyFormatter& keyFormatter,
-                    const boost::optional<Vector2>& position,
+                    const std::optional<Vector2>& position,
                     std::ostream* os) const;
 
   /// Create factor dot.
-  static void DrawFactor(size_t i, const boost::optional<Vector2>& position,
+  static void DrawFactor(size_t i, const std::optional<Vector2>& position,
                          std::ostream* os);
 
   /// Return variable position or none
-  boost::optional<Vector2> variablePos(Key key) const;
+  std::optional<Vector2> variablePos(Key key) const;
 
   /// Draw a single factor, specified by its index i and its variable keys.
   void processFactor(size_t i, const KeyVector& keys,
                      const KeyFormatter& keyFormatter,
-                     const boost::optional<Vector2>& position,
+                     const std::optional<Vector2>& position,
                      std::ostream* os) const;
 };
 
diff --git a/gtsam/inference/EliminateableFactorGraph.h b/gtsam/inference/EliminateableFactorGraph.h
index 900346f7f..c6cf56a11 100644
--- a/gtsam/inference/EliminateableFactorGraph.h
+++ b/gtsam/inference/EliminateableFactorGraph.h
@@ -20,8 +20,8 @@
 
 #include <boost/shared_ptr.hpp>
 #include <functional>
+#include <optional>
 #include <boost/variant.hpp>
-#include <boost/optional.hpp>
 
 #include <gtsam/inference/Ordering.h>
 #include <gtsam/inference/VariableIndex.h>
@@ -92,7 +92,7 @@ namespace gtsam {
     typedef boost::optional<const VariableIndex&> OptionalVariableIndex;
 
     /// Typedef for an optional ordering type
-    typedef boost::optional<Ordering::OrderingType> OptionalOrderingType;
+    typedef std::optional<Ordering::OrderingType> OptionalOrderingType;
 
     /** Do sequential elimination of all variables to produce a Bayes net.  If an ordering is not
      *  provided, the ordering provided by COLAMD will be used.
@@ -111,13 +111,13 @@ namespace gtsam {
      *  \code
      *  VariableIndex varIndex(graph); // Build variable index
      *  Data data = otherFunctionUsingVariableIndex(graph, varIndex); // Other code that uses variable index
-     *  boost::shared_ptr<GaussianBayesNet> result = graph.eliminateSequential(EliminateQR, varIndex, boost::none);
+     *  boost::shared_ptr<GaussianBayesNet> result = graph.eliminateSequential(EliminateQR, varIndex, std::nullopt);
      *  \endcode
      *  */
     boost::shared_ptr<BayesNetType> eliminateSequential(
-      OptionalOrderingType orderingType = boost::none,
+      OptionalOrderingType orderingType = {},
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do sequential elimination of all variables to produce a Bayes net.
      *
@@ -130,13 +130,13 @@ namespace gtsam {
      *  \code
      *  VariableIndex varIndex(graph); // Build variable index
      *  Data data = otherFunctionUsingVariableIndex(graph, varIndex); // Other code that uses variable index
-     *  boost::shared_ptr<GaussianBayesNet> result = graph.eliminateSequential(myOrdering, EliminateQR, varIndex, boost::none);
+     *  boost::shared_ptr<GaussianBayesNet> result = graph.eliminateSequential(myOrdering, EliminateQR, varIndex, std::nullopt);
      *  \endcode
      *  */
     boost::shared_ptr<BayesNetType> eliminateSequential(
       const Ordering& ordering,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do multifrontal elimination of all variables to produce a Bayes tree.  If an ordering is not
      *  provided, the ordering will be computed using either COLAMD or METIS, dependeing on
@@ -151,13 +151,13 @@ namespace gtsam {
      *  \code
      *  VariableIndex varIndex(graph); // Build variable index
      *  Data data = otherFunctionUsingVariableIndex(graph, varIndex); // Other code that uses variable index
-     *  boost::shared_ptr<GaussianBayesTree> result = graph.eliminateMultifrontal(EliminateQR, boost::none, varIndex);
+     *  boost::shared_ptr<GaussianBayesTree> result = graph.eliminateMultifrontal(EliminateQR, {}, varIndex);
      *  \endcode
      *  */
     boost::shared_ptr<BayesTreeType> eliminateMultifrontal(
-      OptionalOrderingType orderingType = boost::none,
+      OptionalOrderingType orderingType = {},
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do multifrontal elimination of all variables to produce a Bayes tree.  If an ordering is not
      *  provided, the ordering will be computed using either COLAMD or METIS, dependeing on
@@ -171,7 +171,7 @@ namespace gtsam {
     boost::shared_ptr<BayesTreeType> eliminateMultifrontal(
       const Ordering& ordering,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do sequential elimination of some variables, in \c ordering provided, to produce a Bayes net
      *  and a remaining factor graph.  This computes the factorization \f$ p(X) = p(A|B) p(B) \f$,
@@ -181,7 +181,7 @@ namespace gtsam {
       eliminatePartialSequential(
       const Ordering& ordering,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do sequential elimination of the given \c variables in an ordering computed by COLAMD to
      *  produce a Bayes net and a remaining factor graph.  This computes the factorization \f$ p(X)
@@ -191,7 +191,7 @@ namespace gtsam {
       eliminatePartialSequential(
       const KeyVector& variables,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do multifrontal elimination of some variables, in \c ordering provided, to produce a Bayes
      *  tree and a remaining factor graph.  This computes the factorization \f$ p(X) = p(A|B) p(B)
@@ -201,7 +201,7 @@ namespace gtsam {
       eliminatePartialMultifrontal(
       const Ordering& ordering,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Do multifrontal elimination of the given \c variables in an ordering computed by COLAMD to
      *  produce a Bayes tree and a remaining factor graph.  This computes the factorization \f$ p(X)
@@ -211,7 +211,7 @@ namespace gtsam {
       eliminatePartialMultifrontal(
       const KeyVector& variables,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Compute the marginal of the requested variables and return the result as a Bayes net.  Uses
      *  COLAMD marginalization ordering by default
@@ -225,7 +225,7 @@ namespace gtsam {
     boost::shared_ptr<BayesNetType> marginalMultifrontalBayesNet(
       boost::variant<const Ordering&, const KeyVector&> variables,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Compute the marginal of the requested variables and return the result as a Bayes net.
      *  @param variables Determines the variables whose marginal to compute, if provided as an
@@ -241,7 +241,7 @@ namespace gtsam {
       boost::variant<const Ordering&, const KeyVector&> variables,
       const Ordering& marginalizedVariableOrdering,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Compute the marginal of the requested variables and return the result as a Bayes tree.  Uses
      *  COLAMD marginalization order by default
@@ -255,7 +255,7 @@ namespace gtsam {
     boost::shared_ptr<BayesTreeType> marginalMultifrontalBayesTree(
       boost::variant<const Ordering&, const KeyVector&> variables,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Compute the marginal of the requested variables and return the result as a Bayes tree.
      *  @param variables Determines the variables whose marginal to compute, if provided as an
@@ -271,13 +271,13 @@ namespace gtsam {
       boost::variant<const Ordering&, const KeyVector&> variables,
       const Ordering& marginalizedVariableOrdering,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
     /** Compute the marginal factor graph of the requested variables. */
     boost::shared_ptr<FactorGraphType> marginal(
       const KeyVector& variables,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const;
+      OptionalVariableIndex variableIndex = {}) const;
 
   private:
 
@@ -301,8 +301,8 @@ namespace gtsam {
     /** @deprecated orderingType specified first for consistency */
     boost::shared_ptr<BayesNetType> GTSAM_DEPRECATED eliminateSequential(
       const Eliminate& function,
-      OptionalVariableIndex variableIndex = boost::none,
-      OptionalOrderingType orderingType = boost::none) const {
+      OptionalVariableIndex variableIndex = {},
+      OptionalOrderingType orderingType = {}) const {
         return eliminateSequential(orderingType, function, variableIndex);
       }
 
@@ -318,8 +318,8 @@ namespace gtsam {
     /** @deprecated orderingType specified first for consistency */
     boost::shared_ptr<BayesTreeType> GTSAM_DEPRECATED eliminateMultifrontal(
       const Eliminate& function,
-      OptionalVariableIndex variableIndex = boost::none,
-      OptionalOrderingType orderingType = boost::none) const {
+      OptionalVariableIndex variableIndex = {},
+      OptionalOrderingType orderingType = {}) const {
         return eliminateMultifrontal(orderingType, function, variableIndex);
       }
 
@@ -328,7 +328,7 @@ namespace gtsam {
       boost::variant<const Ordering&, const KeyVector&> variables,
       boost::none_t,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const {
+      OptionalVariableIndex variableIndex = {}) const {
           return marginalMultifrontalBayesNet(variables, function, variableIndex);
       }
 
@@ -337,7 +337,7 @@ namespace gtsam {
       boost::variant<const Ordering&, const KeyVector&> variables,
       boost::none_t,
       const Eliminate& function = EliminationTraitsType::DefaultEliminate,
-      OptionalVariableIndex variableIndex = boost::none) const {
+      OptionalVariableIndex variableIndex = {}) const {
           return marginalMultifrontalBayesTree(variables, function, variableIndex);
       }
   #endif
diff --git a/gtsam/inference/FactorGraph-inst.h b/gtsam/inference/FactorGraph-inst.h
index 355fdf87e..8460bbe2c 100644
--- a/gtsam/inference/FactorGraph-inst.h
+++ b/gtsam/inference/FactorGraph-inst.h
@@ -155,7 +155,7 @@ void FactorGraph<FACTOR>::dot(std::ostream& os,
     const auto& factor = at(i);
     if (factor) {
       const KeyVector& factorKeys = factor->keys();
-      writer.processFactor(i, factorKeys, keyFormatter, boost::none, &os);
+      writer.processFactor(i, factorKeys, keyFormatter, {}, &os);
     }
   }
 
diff --git a/gtsam/inference/VariableIndex.h b/gtsam/inference/VariableIndex.h
index f934a72af..1357eacdd 100644
--- a/gtsam/inference/VariableIndex.h
+++ b/gtsam/inference/VariableIndex.h
@@ -28,6 +28,7 @@
 
 #include <cassert>
 #include <stdexcept>
+#include <optional>
 
 namespace gtsam {
 
diff --git a/gtsam/nonlinear/GraphvizFormatting.cpp b/gtsam/nonlinear/GraphvizFormatting.cpp
index ca3466b6a..95c6e7faa 100644
--- a/gtsam/nonlinear/GraphvizFormatting.cpp
+++ b/gtsam/nonlinear/GraphvizFormatting.cpp
@@ -34,7 +34,7 @@ Vector2 GraphvizFormatting::findBounds(const Values& values,
   min.y() = std::numeric_limits<double>::infinity();
   for (const Key& key : keys) {
     if (values.exists(key)) {
-      boost::optional<Vector2> xy = extractPosition(values.at(key));
+      std::optional<Vector2> xy = extractPosition(values.at(key));
       if (xy) {
         if (xy->x() < min.x()) min.x() = xy->x();
         if (xy->y() < min.y()) min.y() = xy->y();
@@ -44,7 +44,7 @@ Vector2 GraphvizFormatting::findBounds(const Values& values,
   return min;
 }
 
-boost::optional<Vector2> GraphvizFormatting::extractPosition(
+std::optional<Vector2> GraphvizFormatting::extractPosition(
     const Value& value) const {
   Vector3 t;
   if (const GenericValue<Pose2>* p =
@@ -62,7 +62,7 @@ boost::optional<Vector2> GraphvizFormatting::extractPosition(
       const Eigen::Ref<const Vector3> p_3d(p->value());
       t = p_3d;
     } else {
-      return boost::none;
+      return {};
     }
   } else if (const GenericValue<Pose3>* p =
                  dynamic_cast<const GenericValue<Pose3>*>(&value)) {
@@ -71,7 +71,7 @@ boost::optional<Vector2> GraphvizFormatting::extractPosition(
                  dynamic_cast<const GenericValue<Point3>*>(&value)) {
     t = p->value();
   } else {
-    return boost::none;
+    return {};
   }
   double x, y;
   switch (paperHorizontalAxis) {
@@ -121,11 +121,11 @@ boost::optional<Vector2> GraphvizFormatting::extractPosition(
   return Vector2(x, y);
 }
 
-boost::optional<Vector2> GraphvizFormatting::variablePos(const Values& values,
+std::optional<Vector2> GraphvizFormatting::variablePos(const Values& values,
                                                          const Vector2& min,
                                                          Key key) const {
   if (!values.exists(key)) return DotWriter::variablePos(key);
-  boost::optional<Vector2> xy = extractPosition(values.at(key));
+  std::optional<Vector2> xy = extractPosition(values.at(key));
   if (xy) {
     xy->x() = scale * (xy->x() - min.x());
     xy->y() = scale * (xy->y() - min.y());
@@ -133,11 +133,11 @@ boost::optional<Vector2> GraphvizFormatting::variablePos(const Values& values,
   return xy;
 }
 
-boost::optional<Vector2> GraphvizFormatting::factorPos(const Vector2& min,
+std::optional<Vector2> GraphvizFormatting::factorPos(const Vector2& min,
                                                        size_t i) const {
-  if (factorPositions.size() == 0) return boost::none;
+  if (factorPositions.size() == 0) return {};
   auto it = factorPositions.find(i);
-  if (it == factorPositions.end()) return boost::none;
+  if (it == factorPositions.end()) return {};
   auto pos = it->second;
   return Vector2(scale * (pos.x() - min.x()), scale * (pos.y() - min.y()));
 }
diff --git a/gtsam/nonlinear/GraphvizFormatting.h b/gtsam/nonlinear/GraphvizFormatting.h
index 03cdb3469..fc3cfc95e 100644
--- a/gtsam/nonlinear/GraphvizFormatting.h
+++ b/gtsam/nonlinear/GraphvizFormatting.h
@@ -53,14 +53,14 @@ struct GTSAM_EXPORT GraphvizFormatting : public DotWriter {
   Vector2 findBounds(const Values& values, const KeySet& keys) const;
 
   /// Extract a Vector2 from either Vector2, Pose2, Pose3, or Point3
-  boost::optional<Vector2> extractPosition(const Value& value) const;
+  std::optional<Vector2> extractPosition(const Value& value) const;
 
   /// Return affinely transformed variable position if it exists.
-  boost::optional<Vector2> variablePos(const Values& values, const Vector2& min,
+  std::optional<Vector2> variablePos(const Values& values, const Vector2& min,
                                        Key key) const;
 
   /// Return affinely transformed factor position if it exists.
-  boost::optional<Vector2> factorPos(const Vector2& min, size_t i) const;
+  std::optional<Vector2> factorPos(const Vector2& min, size_t i) const;
 };
 
 }  // namespace gtsam
diff --git a/gtsam/nonlinear/NonlinearFactorGraph.cpp b/gtsam/nonlinear/NonlinearFactorGraph.cpp
index dfa54f26f..3b7efd790 100644
--- a/gtsam/nonlinear/NonlinearFactorGraph.cpp
+++ b/gtsam/nonlinear/NonlinearFactorGraph.cpp
@@ -129,7 +129,7 @@ void NonlinearFactorGraph::dot(std::ostream& os, const Values& values,
     // Create factors and variable connections
     size_t i = 0;
     for (const KeyVector& factorKeys : structure) {
-      writer.processFactor(i++, factorKeys, keyFormatter, boost::none, &os);
+      writer.processFactor(i++, factorKeys, keyFormatter, {}, &os);
     }
   } else {
     // Create factors and variable connections
diff --git a/gtsam/symbolic/tests/testSymbolicBayesTree.cpp b/gtsam/symbolic/tests/testSymbolicBayesTree.cpp
index 0095c9293..f1cc6ee4f 100644
--- a/gtsam/symbolic/tests/testSymbolicBayesTree.cpp
+++ b/gtsam/symbolic/tests/testSymbolicBayesTree.cpp
@@ -213,7 +213,7 @@ TEST(BayesTree, shortcutCheck) {
   // Check if all the cached shortcuts are cleared
   rootClique->deleteCachedShortcuts();
   for (SymbolicBayesTree::sharedClique& clique : allCliques) {
-    bool notCleared = clique->cachedSeparatorMarginal().is_initialized();
+    bool notCleared = clique->cachedSeparatorMarginal().has_value();
     CHECK(notCleared == false);
   }
   EXPECT_LONGS_EQUAL(0, (long)rootClique->numCachedSeparatorMarginals());