diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 28cd7084d44..01165f512fd 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -10,6 +10,7 @@
 #include "clientversion.h"
 #include "consensus/consensus.h"
 #include "consensus/validation.h"
+#include "optional.h"
 #include "validation.h"
 #include "policy/policy.h"
 #include "policy/fees.h"
@@ -179,9 +180,9 @@ bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntr
         // GetMemPoolParents() is only valid for entries in the mempool, so we
         // iterate mapTx to find parents.
         for (unsigned int i = 0; i < tx.vin.size(); i++) {
-            txiter piter = mapTx.find(tx.vin[i].prevout.hash);
+            Optional<txiter> piter = mapTx.find(tx.vin[i].prevout.hash);
             if (piter != mapTx.end()) {
-                parentHashes.insert(piter);
+                parentHashes.insert(*piter);
                 if (parentHashes.size() + 1 > limitAncestorCount) {
                     errString = strprintf("too many unconfirmed parents [limit: %u]", limitAncestorCount);
                     return false;
diff --git a/src/txmempool.h b/src/txmempool.h
index de95d0afd10..e6f1d6fe1f7 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -18,6 +18,7 @@
 #include "coins.h"
 #include "crypto/siphash.h"
 #include "indirectmap.h"
+#include "optional.h"
 #include "primitives/transaction.h"
 #include "sync.h"
 #include "random.h"
diff --git a/src/util.h b/src/util.h
index 9d7ff0bf0fe..d6f212836c6 100644
--- a/src/util.h
+++ b/src/util.h
@@ -17,6 +17,7 @@
 
 #include "compat.h"
 #include "fs.h"
+#include "optional.h"
 #include "tinyformat.h"
 #include "utiltime.h"
 
@@ -62,7 +63,7 @@ extern const char * const BITCOIN_PID_FILENAME;
  */
 inline std::string _(const char* psz)
 {
-    boost::optional<std::string> rv = translationInterface.Translate(psz);
+    Optional<std::string> rv = translationInterface.Translate(psz);
     return rv ? (*rv) : psz;
 }
 
diff --git a/src/wallet/coincontrol.h b/src/wallet/coincontrol.h
index 20dcae890c1..a5d72c0c53f 100644
--- a/src/wallet/coincontrol.h
+++ b/src/wallet/coincontrol.h
@@ -6,6 +6,7 @@
 #ifndef BITCOIN_WALLET_COINCONTROL_H
 #define BITCOIN_WALLET_COINCONTROL_H
 
+#include "optional.h"
 #include "primitives/transaction.h"
 #include "dogecoin-fees.h"