diff --git a/src/core_read.cpp b/src/core_read.cpp
index 0eba29a5cd..a98e9e046a 100644
--- a/src/core_read.cpp
+++ b/src/core_read.cpp
@@ -16,7 +16,6 @@
 #include <version.h>
 
 #include <boost/algorithm/string/classification.hpp>
-#include <boost/algorithm/string/replace.hpp>
 #include <boost/algorithm/string/split.hpp>
 
 #include <algorithm>
@@ -41,8 +40,9 @@ CScript ParseScript(const std::string& s)
             std::string strName(name);
             mapOpNames[strName] = static_cast<opcodetype>(op);
             // Convenience: OP_ADD and just ADD are both recognized:
-            boost::algorithm::replace_first(strName, "OP_", "");
-            mapOpNames[strName] = static_cast<opcodetype>(op);
+            if (strName.compare(0, 3, "OP_") == 0) {  // strName starts with "OP_"
+                mapOpNames[strName.substr(3)] = static_cast<opcodetype>(op);
+            }
         }
     }
 
diff --git a/src/init.cpp b/src/init.cpp
index dc8e2c6abf..8d193e92a1 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -852,6 +852,10 @@ static void ThreadImport(std::vector<fs::path> vImportFiles)
                 break; // This error is logged in OpenBlockFile
             LogPrintf("Reindexing block file blk%05u.dat...\n", (unsigned int)nFile);
             LoadExternalBlockFile(chainparams, file, &pos);
+            if (ShutdownRequested()) {
+                LogPrintf("Shutdown requested. Exit %s\n", __func__);
+                return;
+            }
             nFile++;
         }
         pblocktree->WriteReindexing(false);
@@ -881,6 +885,10 @@ static void ThreadImport(std::vector<fs::path> vImportFiles)
         if (file) {
             LogPrintf("Importing blocks file %s...\n", path.string());
             LoadExternalBlockFile(chainparams, file);
+            if (ShutdownRequested()) {
+                LogPrintf("Shutdown requested. Exit %s\n", __func__);
+                return;
+            }
         } else {
             LogPrintf("Warning: Could not open blocks file %s\n", path.string());
         }
diff --git a/src/netbase.cpp b/src/netbase.cpp
index a17934e717..13483a9d57 100644
--- a/src/netbase.cpp
+++ b/src/netbase.cpp
@@ -23,7 +23,6 @@
 #include <codecvt>
 #endif
 
-#include <boost/algorithm/string/case_conv.hpp> // for to_lower()
 #ifdef USE_POLL
 #include <poll.h>
 #endif
@@ -44,7 +43,7 @@ static const int SOCKS5_RECV_TIMEOUT = 20 * 1000;
 static std::atomic<bool> interruptSocks5Recv(false);
 
 enum Network ParseNetwork(std::string net) {
-    boost::to_lower(net);
+    Downcase(net);
     if (net == "ipv4") return NET_IPV4;
     if (net == "ipv6") return NET_IPV6;
     if (net == "onion") return NET_ONION;
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index b8700f163c..7712037eab 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -17,7 +17,6 @@
 
 #include <boost/bind.hpp>
 #include <boost/signals2/signal.hpp>
-#include <boost/algorithm/string/case_conv.hpp> // for to_upper()
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
 
@@ -248,9 +247,7 @@ std::string CRPCTable::help(const std::string& strCommand, const std::string& st
                     if (!category.empty())
                         strRet += "\n";
                     category = pcmd->category;
-                    std::string firstLetter = category.substr(0,1);
-                    boost::to_upper(firstLetter);
-                    strRet += "== " + firstLetter + category.substr(1) + " ==\n";
+                    strRet += "== " + Capitalize(category) + " ==\n";
                 }
             }
             strRet += strHelp + "\n";
diff --git a/src/test/netbase_tests.cpp b/src/test/netbase_tests.cpp
index cdb2304ca8..92d5e2c76c 100644
--- a/src/test/netbase_tests.cpp
+++ b/src/test/netbase_tests.cpp
@@ -431,4 +431,22 @@ BOOST_AUTO_TEST_CASE(caddress_unserialize_v2)
     BOOST_CHECK(fixture_addresses == addresses_unserialized);
 }
 
+BOOST_AUTO_TEST_CASE(netbase_parsenetwork)
+{
+    BOOST_CHECK_EQUAL(ParseNetwork("ipv4"), NET_IPV4);
+    BOOST_CHECK_EQUAL(ParseNetwork("ipv6"), NET_IPV6);
+    BOOST_CHECK_EQUAL(ParseNetwork("onion"), NET_ONION);
+    BOOST_CHECK_EQUAL(ParseNetwork("tor"), NET_ONION);
+
+    BOOST_CHECK_EQUAL(ParseNetwork("IPv4"), NET_IPV4);
+    BOOST_CHECK_EQUAL(ParseNetwork("IPv6"), NET_IPV6);
+    BOOST_CHECK_EQUAL(ParseNetwork("ONION"), NET_ONION);
+    BOOST_CHECK_EQUAL(ParseNetwork("TOR"), NET_ONION);
+
+    BOOST_CHECK_EQUAL(ParseNetwork(":)"), NET_UNROUTABLE);
+    BOOST_CHECK_EQUAL(ParseNetwork("tÖr"), NET_UNROUTABLE);
+    BOOST_CHECK_EQUAL(ParseNetwork("\xfe\xff"), NET_UNROUTABLE);
+    BOOST_CHECK_EQUAL(ParseNetwork(""), NET_UNROUTABLE);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 2b564d8512..aab2331866 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -1289,4 +1289,43 @@ BOOST_AUTO_TEST_CASE(test_tracked_vector)
     BOOST_CHECK_EQUAL(v8[2].copies, 0);
 }
 
+BOOST_AUTO_TEST_CASE(test_ToLower)
+{
+    BOOST_CHECK_EQUAL(ToLower('@'), '@');
+    BOOST_CHECK_EQUAL(ToLower('A'), 'a');
+    BOOST_CHECK_EQUAL(ToLower('Z'), 'z');
+    BOOST_CHECK_EQUAL(ToLower('['), '[');
+    BOOST_CHECK_EQUAL(ToLower(0), 0);
+    BOOST_CHECK_EQUAL(ToLower(255), 255);
+
+    std::string testVector;
+    Downcase(testVector);
+    BOOST_CHECK_EQUAL(testVector, "");
+
+    testVector = "#HODL";
+    Downcase(testVector);
+    BOOST_CHECK_EQUAL(testVector, "#hodl");
+
+    testVector = "\x00\xfe\xff";
+    Downcase(testVector);
+    BOOST_CHECK_EQUAL(testVector, "\x00\xfe\xff");
+}
+
+BOOST_AUTO_TEST_CASE(test_ToUpper)
+{
+    BOOST_CHECK_EQUAL(ToUpper('`'), '`');
+    BOOST_CHECK_EQUAL(ToUpper('a'), 'A');
+    BOOST_CHECK_EQUAL(ToUpper('z'), 'Z');
+    BOOST_CHECK_EQUAL(ToUpper('{'), '{');
+    BOOST_CHECK_EQUAL(ToUpper(0), 0);
+    BOOST_CHECK_EQUAL(ToUpper(255), 255);
+}
+
+BOOST_AUTO_TEST_CASE(test_Capitalize)
+{
+    BOOST_CHECK_EQUAL(Capitalize(""), "");
+    BOOST_CHECK_EQUAL(Capitalize("bitcoin"), "Bitcoin");
+    BOOST_CHECK_EQUAL(Capitalize("\x00\xfe\xff"), "\x00\xfe\xff");
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
index 5dda538e41..47456440ed 100644
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -8,6 +8,7 @@
 
 #include <tinyformat.h>
 
+#include <algorithm>
 #include <cstdlib>
 #include <cstring>
 #include <errno.h>
@@ -615,3 +616,15 @@ std::string HexStr(const Span<const uint8_t> s)
     }
     return rv;
 }
+
+void Downcase(std::string& str)
+{
+    std::transform(str.begin(), str.end(), str.begin(), [](unsigned char c){return ToLower(c);});
+}
+
+std::string Capitalize(std::string str)
+{
+    if (str.empty()) return str;
+    str[0] = ToUpper(str.front());
+    return str;
+}
diff --git a/src/util/strencodings.h b/src/util/strencodings.h
index 3ebc0bf32f..711cf5bcf1 100644
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -188,6 +188,50 @@ bool ConvertBits(const O& outfn, I it, I end) {
     return true;
 }
 
+/**
+ * Converts the given character to its lowercase equivalent.
+ * This function is locale independent. It only converts uppercase
+ * characters in the standard 7-bit ASCII range.
+ * @param[in] c     the character to convert to lowercase.
+ * @return          the lowercase equivalent of c; or the argument
+ *                  if no conversion is possible.
+ */
+constexpr unsigned char ToLower(unsigned char c)
+{
+    return (c >= 'A' && c <= 'Z' ? (c - 'A') + 'a' : c);
+}
+
+/**
+ * Converts the given string to its lowercase equivalent.
+ * This function is locale independent. It only converts uppercase
+ * characters in the standard 7-bit ASCII range.
+ * @param[in,out] str   the string to convert to lowercase.
+ */
+void Downcase(std::string& str);
+
+/**
+ * Converts the given character to its uppercase equivalent.
+ * This function is locale independent. It only converts lowercase
+ * characters in the standard 7-bit ASCII range.
+ * @param[in] c     the character to convert to uppercase.
+ * @return          the uppercase equivalent of c; or the argument
+ *                  if no conversion is possible.
+ */
+constexpr unsigned char ToUpper(unsigned char c)
+{
+    return (c >= 'a' && c <= 'z' ? (c - 'a') + 'A' : c);
+}
+
+/**
+ * Capitalizes the first character of the given string.
+ * This function is locale independent. It only capitalizes the
+ * first character of the argument if it has an uppercase equivalent
+ * in the standard 7-bit ASCII range.
+ * @param[in] str   the string to capitalize.
+ * @return          string with the first letter capitalized.
+ */
+std::string Capitalize(std::string str);
+
 /** Parse an HD keypaths like "m/7/0'/2000". */
 bool ParseHDKeypath(const std::string& keypath_str, std::vector<uint32_t>& keypath);
 
diff --git a/src/validation.cpp b/src/validation.cpp
index d469e0b312..5a027ba8ab 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -4836,7 +4836,7 @@ bool LoadGenesisBlock(const CChainParams& chainparams)
     return g_chainstate.LoadGenesisBlock(chainparams);
 }
 
-bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos *dbp)
+void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos* dbp)
 {
     // Map of disk positions for blocks with unknown parent (only used for reindex)
     static std::multimap<uint256, CDiskBlockPos> mapBlocksUnknownParent;
@@ -4849,7 +4849,7 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
         CBufferedFile blkdat(fileIn, 2*nMaxBlockSize, nMaxBlockSize+8, SER_DISK, CLIENT_VERSION);
         uint64_t nRewind = blkdat.GetPos();
         while (!blkdat.eof()) {
-            boost::this_thread::interruption_point();
+            if (ShutdownRequested()) return;
 
             blkdat.SetPos(nRewind);
             nRewind++; // start one byte further next time, in case of failure
@@ -4953,9 +4953,7 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
     } catch (const std::runtime_error& e) {
         AbortNode(std::string("System error: ") + e.what());
     }
-    if (nLoaded > 0)
-        LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart);
-    return nLoaded > 0;
+    LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart);
 }
 
 void CChainState::CheckBlockIndex(const Consensus::Params& consensusParams)
diff --git a/src/validation.h b/src/validation.h
index 33ef386178..f16f3c2990 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -267,7 +267,7 @@ FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly = false);
 /** Translation to a filesystem path */
 fs::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix);
 /** Import blocks from an external file */
-bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos *dbp = nullptr);
+void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos* dbp = nullptr);
 /** Ensures we have a genesis block in the block tree, possibly writing one to disk. */
 bool LoadGenesisBlock(const CChainParams& chainparams);
 /** Load the block tree and coins database from disk,
diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index 085cea8d7c..0393a43481 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -17,8 +17,6 @@
 #include <sys/stat.h>
 #endif
 
-#include <boost/thread.hpp>
-
 namespace {
 
 //! Make sure database has a unique fileid within the environment. If it
@@ -153,10 +151,9 @@ BerkeleyEnvironment::~BerkeleyEnvironment()
 
 bool BerkeleyEnvironment::Open(bool retry)
 {
-    if (fDbEnvInit)
+    if (fDbEnvInit) {
         return true;
-
-    boost::this_thread::interruption_point();
+    }
 
     fs::path pathIn = strPath;
     TryCreateDirectories(pathIn);
@@ -225,13 +222,11 @@ bool BerkeleyEnvironment::Open(bool retry)
     return true;
 }
 
-//! Construct an in-memory mock Berkeley environment for testing and as a place-holder for g_dbenvs emplace
+//! Construct an in-memory mock Berkeley environment for testing
 BerkeleyEnvironment::BerkeleyEnvironment()
 {
     Reset();
 
-    boost::this_thread::interruption_point();
-
     LogPrint(BCLog::DB, "BerkeleyEnvironment::MakeMock\n");
 
     dbenv->set_cachesize(1, 0, 1);
@@ -250,8 +245,9 @@ BerkeleyEnvironment::BerkeleyEnvironment()
                              DB_THREAD |
                              DB_PRIVATE,
                          S_IRUSR | S_IWUSR);
-    if (ret > 0)
+    if (ret > 0) {
         throw std::runtime_error(strprintf("BerkeleyEnvironment::MakeMock: Error %d opening database environment.", ret));
+    }
 
     fDbEnvInit = true;
     fMockDb = true;
@@ -772,7 +768,6 @@ bool BerkeleyBatch::PeriodicFlush(BerkeleyDatabase& database)
 
         if (nRefCount == 0)
         {
-            boost::this_thread::interruption_point();
             std::map<std::string, int>::iterator mi = env->mapFileUseCount.find(strFile);
             if (mi != env->mapFileUseCount.end())
             {
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 7520f16d79..8d777e205b 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -21,8 +21,6 @@
 
 #include <atomic>
 
-#include <boost/thread.hpp>
-
 //
 // WalletBatch
 //
@@ -666,11 +664,7 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
         // Store initial external keypool size since we mostly use external keys in mixing
         pwallet->nKeysLeftSinceAutoBackup = pwallet->KeypoolCountExternalKeys();
         pwallet->WalletLogPrintf("nKeysLeftSinceAutoBackup: %d\n", pwallet->nKeysLeftSinceAutoBackup);
-    }
-    catch (const boost::thread_interrupted&) {
-        throw;
-    }
-    catch (...) {
+    } catch (...) {
         result = DBErrors::CORRUPT;
     }
 
@@ -762,11 +756,7 @@ DBErrors WalletBatch::FindWalletTx(std::vector<uint256>& vTxHash, std::vector<CW
             }
         }
         pcursor->close();
-    }
-    catch (const boost::thread_interrupted&) {
-        throw;
-    }
-    catch (...) {
+    } catch (...) {
         result = DBErrors::CORRUPT;
     }
 
diff --git a/test/lint/lint-includes.sh b/test/lint/lint-includes.sh
index da57ce0163..02ca9baa0f 100755
--- a/test/lint/lint-includes.sh
+++ b/test/lint/lint-includes.sh
@@ -50,7 +50,6 @@ fi
 
 EXPECTED_BOOST_INCLUDES=(
     boost/algorithm/string.hpp
-    boost/algorithm/string/case_conv.hpp
     boost/algorithm/string/classification.hpp
     boost/algorithm/string/replace.hpp
     boost/algorithm/string/split.hpp
diff --git a/test/lint/lint-locale-dependence.sh b/test/lint/lint-locale-dependence.sh
index 938fadfc79..1cb9feb6b9 100755
--- a/test/lint/lint-locale-dependence.sh
+++ b/test/lint/lint-locale-dependence.sh
@@ -15,11 +15,9 @@ KNOWN_VIOLATIONS=(
     "src/governance/governance-validators.cpp.*tolower"
     "src/httprpc.cpp.*trim"
     "src/init.cpp:.*atoi"
-    "src/netbase.cpp.*to_lower"
     "src/qt/rpcconsole.cpp:.*atoi"
     "src/qt/rpcconsole.cpp:.*isdigit"
     "src/rest.cpp:.*strtol"
-    "src/rpc/server.cpp.*to_upper"
     "src/rpc/blockchain.cpp.*atoi"
     "src/rpc/governance.cpp.*atoi"
     "src/rpc/masternode.cpp.*atoi"