diff --git a/domain-server/src/DomainGatekeeper.cpp b/domain-server/src/DomainGatekeeper.cpp
index 6377a37f34..342b8213d1 100644
--- a/domain-server/src/DomainGatekeeper.cpp
+++ b/domain-server/src/DomainGatekeeper.cpp
@@ -62,10 +62,7 @@ void DomainGatekeeper::processConnectRequestPacket(QSharedPointer<ReceivedMessag
 
     QByteArray myProtocolVersion = protocolVersionsSignature();
     if (nodeConnection.protocolVersion != myProtocolVersion) {
-        QString protocolVersionError = "Protocol version mismatch - Domain version:" + QCoreApplication::applicationVersion();
-        qDebug() << "Protocol Version mismatch - denying connection.";
-        sendConnectionDeniedPacket(protocolVersionError, message->getSenderSockAddr(),
-                DomainHandler::ConnectionRefusedReason::ProtocolMismatch);
+        sendProtocolMismatchConnectionDenial(message->getSenderSockAddr());
         return;
     }
 
@@ -514,15 +511,24 @@ void DomainGatekeeper::publicKeyJSONCallback(QNetworkReply& requestReply) {
     }
 }
 
+void DomainGatekeeper::sendProtocolMismatchConnectionDenial(const HifiSockAddr& senderSockAddr) {
+    QString protocolVersionError = "Protocol version mismatch - Domain version: " + QCoreApplication::applicationVersion();
+
+    qDebug() << "Protocol Version mismatch - denying connection.";
+
+    sendConnectionDeniedPacket(protocolVersionError, senderSockAddr,
+                               DomainHandler::ConnectionRefusedReason::ProtocolMismatch);
+}
+
 void DomainGatekeeper::sendConnectionDeniedPacket(const QString& reason, const HifiSockAddr& senderSockAddr,
-            DomainHandler::ConnectionRefusedReason reasonCode) {
+                                                  DomainHandler::ConnectionRefusedReason reasonCode) {
     // this is an agent and we've decided we won't let them connect - send them a packet to deny connection
     QByteArray utfString = reason.toUtf8();
     quint16 payloadSize = utfString.size();
 
     // setup the DomainConnectionDenied packet
     auto connectionDeniedPacket = NLPacket::create(PacketType::DomainConnectionDenied,
-                                                payloadSize + sizeof(payloadSize) + sizeof(uint8_t));
+                                                   payloadSize + sizeof(payloadSize) + sizeof(uint8_t));
 
     // pack in the reason the connection was denied (the client displays this)
     if (payloadSize > 0) {
diff --git a/domain-server/src/DomainGatekeeper.h b/domain-server/src/DomainGatekeeper.h
index bac50af2ec..50bbf38543 100644
--- a/domain-server/src/DomainGatekeeper.h
+++ b/domain-server/src/DomainGatekeeper.h
@@ -42,6 +42,8 @@ public:
     void preloadAllowedUserPublicKeys();
     
     void removeICEPeer(const QUuid& peerUUID) { _icePeers.remove(peerUUID); }
+
+    static void sendProtocolMismatchConnectionDenial(const HifiSockAddr& senderSockAddr);
 public slots:
     void processConnectRequestPacket(QSharedPointer<ReceivedMessage> message);
     void processICEPingPacket(QSharedPointer<ReceivedMessage> message);
@@ -76,8 +78,8 @@ private:
                                        const HifiSockAddr& senderSockAddr);
     
     void sendConnectionTokenPacket(const QString& username, const HifiSockAddr& senderSockAddr);
-    void sendConnectionDeniedPacket(const QString& reason, const HifiSockAddr& senderSockAddr, 
-                    DomainHandler::ConnectionRefusedReason reasonCode = DomainHandler::ConnectionRefusedReason::Unknown);
+    static void sendConnectionDeniedPacket(const QString& reason, const HifiSockAddr& senderSockAddr,
+            DomainHandler::ConnectionRefusedReason reasonCode = DomainHandler::ConnectionRefusedReason::Unknown);
     
     void pingPunchForConnectingPeer(const SharedNetworkPeer& peer);
     
diff --git a/domain-server/src/DomainServer.cpp b/domain-server/src/DomainServer.cpp
index 5bc447a225..7c596bb187 100644
--- a/domain-server/src/DomainServer.cpp
+++ b/domain-server/src/DomainServer.cpp
@@ -325,16 +325,11 @@ bool DomainServer::packetVersionMatch(const udt::Packet& packet) {
 
     auto nodeList = DependencyManager::get<LimitedNodeList>();
 
-    // This implements a special case that handles OLD clients which don't know how to negotiate matching
-    // protocol versions. We know these clients will sent DomainConnectRequest with older versions. We also
-    // know these clients will show a warning dialog if they get an EntityData with a protocol version they
-    // don't understand, so we can send them an empty EntityData with our latest version and they will
-    // warn the user that the protocol is not compatible
-    if (headerType == PacketType::DomainConnectRequest &&
-        headerVersion < static_cast<PacketVersion>(DomainConnectRequestVersion::HasProtocolVersions)) {
-        auto packetWithBadVersion = NLPacket::create(PacketType::EntityData);
-        nodeList->sendPacket(std::move(packetWithBadVersion), packet.getSenderSockAddr());
-        return false;
+    // if this is a mismatching connect packet, we can't simply drop it on the floor
+    // send back a packet to the interface that tells them we refuse connection for a mismatch
+    if (headerType == PacketType::DomainConnectRequest
+        && headerVersion != versionForPacketType(PacketType::DomainConnectRequest)) {
+        DomainGatekeeper::sendProtocolMismatchConnectionDenial(packet.getSenderSockAddr());
     }
 
     // let the normal nodeList implementation handle all other packets.
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 3f943b212d..49c2e17d84 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -630,7 +630,6 @@ Application::Application(int& argc, char** argv, QElapsedTimer& startupTimer) :
     connect(&domainHandler, SIGNAL(connectedToDomain(const QString&)), SLOT(updateWindowTitle()));
     connect(&domainHandler, SIGNAL(disconnectedFromDomain()), SLOT(updateWindowTitle()));
     connect(&domainHandler, SIGNAL(disconnectedFromDomain()), SLOT(clearDomainOctreeDetails()));
-    connect(&domainHandler, &DomainHandler::resetting, nodeList.data(), &NodeList::resetDomainServerCheckInVersion);
     connect(&domainHandler, &DomainHandler::domainConnectionRefused, this, &Application::domainConnectionRefused);
 
     // update our location every 5 seconds in the metaverse server, assuming that we are authenticated with one
@@ -654,9 +653,11 @@ Application::Application(int& argc, char** argv, QElapsedTimer& startupTimer) :
     connect(nodeList.data(), &NodeList::nodeActivated, this, &Application::nodeActivated);
     connect(nodeList.data(), &NodeList::uuidChanged, getMyAvatar(), &MyAvatar::setSessionUUID);
     connect(nodeList.data(), &NodeList::uuidChanged, this, &Application::setSessionUUID);
-    connect(nodeList.data(), &NodeList::limitOfSilentDomainCheckInsReached, this, &Application::limitOfSilentDomainCheckInsReached);
     connect(nodeList.data(), &NodeList::packetVersionMismatch, this, &Application::notifyPacketVersionMismatch);
 
+    // you might think we could just do this in NodeList but we only want this connection for Interface
+    connect(nodeList.data(), &NodeList::limitOfSilentDomainCheckInsReached, nodeList.data(), &NodeList::reset);
+
     // connect to appropriate slots on AccountManager
     auto accountManager = DependencyManager::get<AccountManager>();
 
@@ -1074,8 +1075,6 @@ Application::Application(int& argc, char** argv, QElapsedTimer& startupTimer) :
 void Application::domainConnectionRefused(const QString& reasonMessage, int reasonCode) {
     switch (static_cast<DomainHandler::ConnectionRefusedReason>(reasonCode)) {
         case DomainHandler::ConnectionRefusedReason::ProtocolMismatch:
-            notifyPacketVersionMismatch();
-            break;
         case DomainHandler::ConnectionRefusedReason::TooManyUsers:
         case DomainHandler::ConnectionRefusedReason::Unknown: {
             QString message = "Unable to connect to the location you are visiting.\n";
@@ -4619,17 +4618,6 @@ void Application::setSessionUUID(const QUuid& sessionUUID) const {
     Physics::setSessionUUID(sessionUUID);
 }
 
-
-// If we're not getting anything back from the domain server checkin, it might be that the domain speaks an 
-// older version of the DomainConnectRequest protocol. We will attempt to send and older version of DomainConnectRequest.
-// We won't actually complete the connection, but if the server responds, we know that it needs to be upgraded (or we
-// need to be downgraded to talk to it).
-void Application::limitOfSilentDomainCheckInsReached() {
-    auto nodeList = DependencyManager::get<NodeList>();
-    nodeList->downgradeDomainServerCheckInVersion(); // attempt to use an older domain checkin version
-    nodeList->reset();
-}
-
 bool Application::askToSetAvatarUrl(const QString& url) {
     QUrl realUrl(url);
     if (realUrl.isLocalFile()) {
diff --git a/interface/src/Application.h b/interface/src/Application.h
index f93434f581..6b6148be32 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -318,7 +318,6 @@ private slots:
     bool displayAvatarAttachmentConfirmationDialog(const QString& name) const;
 
     void setSessionUUID(const QUuid& sessionUUID) const;
-    void limitOfSilentDomainCheckInsReached();
 
     void domainChanged(const QString& domainHostname);
     void updateWindowTitle() const;
diff --git a/interface/src/CrashReporter.cpp b/interface/src/CrashReporter.cpp
index 1fd534ffac..596c34ca92 100644
--- a/interface/src/CrashReporter.cpp
+++ b/interface/src/CrashReporter.cpp
@@ -10,16 +10,20 @@
 //
 
 
-#ifdef HAS_BUGSPLAT
+#include "Application.h"
 #include "CrashReporter.h"
 
+#ifdef _WIN32
 #include <new.h>
 #include <Windows.h>
+#include <DbgHelp.h>
 
 #include <csignal>
-
 #include <QDebug>
 
+
+#pragma comment(lib, "Dbghelp.lib")
+
 // SetUnhandledExceptionFilter can be overridden by the CRT at the point that an error occurs. More information
 // can be found here: http://www.codeproject.com/Articles/154686/SetUnhandledExceptionFilter-and-the-C-C-Runtime-Li
 // A fairly common approach is to patch the SetUnhandledExceptionFilter so that it cannot be overridden and so
@@ -77,13 +81,37 @@ BOOL redirectLibraryFunctionToFunction(char* library, char* function, void* fn)
     return bRet;
 }
 
+void printStackTrace(ULONG framesToSkip = 1) {
+    HANDLE process = GetCurrentProcess();
+    SymInitialize(process, NULL, TRUE);
+    void* stack[100];
+    uint16_t frames = CaptureStackBackTrace(framesToSkip, 100, stack, NULL);
+    SYMBOL_INFO* symbol = (SYMBOL_INFO *)calloc(sizeof(SYMBOL_INFO) + 256 * sizeof(char), 1);
+    symbol->MaxNameLen = 255;
+    symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
+
+    for (uint16_t i = 0; i < frames; ++i) {
+        SymFromAddr(process, (DWORD64)(stack[i]), 0, symbol);
+        qWarning() << QString("%1: %2 - 0x%0X").arg(QString::number(frames - i - 1), QString(symbol->Name), QString::number(symbol->Address, 16));
+    }
+
+    free(symbol);
+
+    // Try to force the log to sync to the filesystem
+    auto app = qApp;
+    if (app && app->getLogger()) {
+        app->getLogger()->sync();
+    }
+}
 
 void handleSignal(int signal) {
     // Throw so BugSplat can handle
     throw(signal);
 }
 
-void handlePureVirtualCall() {
+void __cdecl handlePureVirtualCall() {
+    qWarning() << "Pure virtual function call detected";
+    printStackTrace(2);
     // Throw so BugSplat can handle
     throw("ERROR: Pure virtual call");
 }
@@ -107,6 +135,8 @@ _purecall_handler __cdecl noop_set_purecall_handler(_purecall_handler pNew) {
     return nullptr;
 }
 
+#ifdef HAS_BUGSPLAT
+
 static const DWORD BUG_SPLAT_FLAGS = MDSF_PREVENTHIJACKING | MDSF_USEGUARDMEMORY;
 
 CrashReporter::CrashReporter(QString bugSplatDatabase, QString bugSplatApplicationName, QString version)
@@ -133,3 +163,4 @@ CrashReporter::CrashReporter(QString bugSplatDatabase, QString bugSplatApplicati
     }
 }
 #endif
+#endif
diff --git a/interface/src/FileLogger.cpp b/interface/src/FileLogger.cpp
index f5f7ce6ebe..50f7d15d6b 100644
--- a/interface/src/FileLogger.cpp
+++ b/interface/src/FileLogger.cpp
@@ -115,3 +115,7 @@ QString FileLogger::getLogData() {
     }
     return result;
 }
+
+void FileLogger::sync() {
+    _persistThreadInstance->waitIdle();
+}
diff --git a/interface/src/FileLogger.h b/interface/src/FileLogger.h
index e9bae63a73..28ac6fba40 100644
--- a/interface/src/FileLogger.h
+++ b/interface/src/FileLogger.h
@@ -28,6 +28,7 @@ public:
     virtual void addMessage(const QString&) override;
     virtual QString getLogData() override;
     virtual void locateLog() override;
+    void sync();
 
 signals:
     void rollingLogFile(QString newFilename);
diff --git a/interface/src/Menu.cpp b/interface/src/Menu.cpp
index 90c593e732..b37f70f65d 100644
--- a/interface/src/Menu.cpp
+++ b/interface/src/Menu.cpp
@@ -542,6 +542,9 @@ Menu::Menu() {
     #if (PR_BUILD || DEV_BUILD)
     addCheckableActionToQMenuAndActionHash(networkMenu, MenuOption::SendWrongProtocolVersion, 0, false,
                 qApp, SLOT(sendWrongProtocolVersionsSignature(bool)));
+
+    addCheckableActionToQMenuAndActionHash(networkMenu, MenuOption::SendWrongDSConnectVersion, 0, false,
+                                           nodeList.data(), SLOT(toggleSendNewerDSConnectVersion(bool)));
     #endif
 
     
diff --git a/interface/src/Menu.h b/interface/src/Menu.h
index 8081e27eb8..503cbf51fa 100644
--- a/interface/src/Menu.h
+++ b/interface/src/Menu.h
@@ -166,6 +166,7 @@ namespace MenuOption {
     const QString RunTimingTests = "Run Timing Tests";
     const QString ScriptEditor = "Script Editor...";
     const QString ScriptedMotorControl = "Enable Scripted Motor Control";
+    const QString SendWrongDSConnectVersion = "Send wrong DS connect version";
     const QString SendWrongProtocolVersion = "Send wrong protocol version";
     const QString SetHomeLocation = "Set Home Location";
     const QString ShowDSConnectTable = "Show Domain Connection Timing";
diff --git a/libraries/audio/src/AudioHRTF.cpp b/libraries/audio/src/AudioHRTF.cpp
index 7fadf073a1..e7cf4436c6 100644
--- a/libraries/audio/src/AudioHRTF.cpp
+++ b/libraries/audio/src/AudioHRTF.cpp
@@ -10,7 +10,6 @@
 //
 
 #include <math.h>
-#include <stdint.h>
 #include <string.h>
 #include <assert.h>
 
@@ -119,68 +118,18 @@ static void FIR_1x4_SSE(float* src, float* dst0, float* dst1, float* dst2, float
     }
 }
 
-//
-// Detect AVX/AVX2 support
-//
-
-#if defined(_MSC_VER)
-
-#include <intrin.h>
-
-static bool cpuSupportsAVX() {
-    int info[4];
-    int mask = (1 << 27) | (1 << 28);   // OSXSAVE and AVX
-
-    __cpuidex(info, 0x1, 0);
-
-    bool result = false;
-    if ((info[2] & mask) == mask) {
-
-        if ((_xgetbv(_XCR_XFEATURE_ENABLED_MASK) & 0x6) == 0x6) {
-            result = true;
-        }
-    }
-    return result;
-}
-
-#elif defined(__GNUC__)
-
-#include <cpuid.h>
-
-static bool cpuSupportsAVX() {
-    unsigned int eax, ebx, ecx, edx;
-    unsigned int mask = (1 << 27) | (1 << 28);   // OSXSAVE and AVX
-
-    bool result = false;
-    if (__get_cpuid(0x1, &eax, &ebx, &ecx, &edx) && ((ecx & mask) == mask)) {
-
-        __asm__("xgetbv" : "=a"(eax), "=d"(edx) : "c"(0));
-        if ((eax & 0x6) == 0x6) {
-            result = true;
-        }
-    }
-    return result;    
-}
-
-#else
-
-static bool cpuSupportsAVX() {
-    return false;
-}
-
-#endif
-
 //
 // Runtime CPU dispatch
 //
 
-typedef void FIR_1x4_t(float* src, float* dst0, float* dst1, float* dst2, float* dst3, float coef[4][HRTF_TAPS], int numFrames);
-FIR_1x4_t FIR_1x4_AVX;  // separate compilation with VEX-encoding enabled
+#include "CPUDetect.h"
+
+void FIR_1x4_AVX(float* src, float* dst0, float* dst1, float* dst2, float* dst3, float coef[4][HRTF_TAPS], int numFrames);
 
 static void FIR_1x4(float* src, float* dst0, float* dst1, float* dst2, float* dst3, float coef[4][HRTF_TAPS], int numFrames) {
 
-    static FIR_1x4_t* f = cpuSupportsAVX() ? FIR_1x4_AVX : FIR_1x4_SSE; // init on first call
-    (*f)(src, dst0, dst1, dst2, dst3, coef, numFrames);                 // dispatch
+    static auto f = cpuSupportsAVX() ? FIR_1x4_AVX : FIR_1x4_SSE;
+    (*f)(src, dst0, dst1, dst2, dst3, coef, numFrames); // dispatch
 }
 
 // 4 channel planar to interleaved
diff --git a/libraries/audio/src/AudioHRTF.h b/libraries/audio/src/AudioHRTF.h
index f92f9c1602..d3b6237d0c 100644
--- a/libraries/audio/src/AudioHRTF.h
+++ b/libraries/audio/src/AudioHRTF.h
@@ -32,7 +32,7 @@ public:
     // input: mono source
     // output: interleaved stereo mix buffer (accumulates into existing output)
     // index: HRTF subject index
-    // azimuth: clockwise panning angle [0, 360] in degrees
+    // azimuth: clockwise panning angle in radians
     // gain: gain factor for distance attenuation
     // numFrames: must be HRTF_BLOCK in this version
     //
diff --git a/libraries/networking/src/AddressManager.cpp b/libraries/networking/src/AddressManager.cpp
index 1b7ed11cce..80989acd2c 100644
--- a/libraries/networking/src/AddressManager.cpp
+++ b/libraries/networking/src/AddressManager.cpp
@@ -144,12 +144,21 @@ bool AddressManager::handleUrl(const QUrl& lookupUrl, LookupTrigger trigger) {
         // 4. domain network address (IP or dns resolvable hostname)
 
         // use our regex'ed helpers to figure out what we're supposed to do with this
-        if (!handleUsername(lookupUrl.authority())) {
+        if (handleUsername(lookupUrl.authority())) {
+            // handled a username for lookup
+
+            // in case we're failing to connect to where we thought this user was
+            // store their username as previous lookup so we can refresh their location via API
+            _previousLookup = lookupUrl;
+        } else {
             // we're assuming this is either a network address or global place name
             // check if it is a network address first
             bool hostChanged;
             if (handleNetworkAddress(lookupUrl.host()
-                                      + (lookupUrl.port() == -1 ? "" : ":" + QString::number(lookupUrl.port())), trigger, hostChanged)) {
+                                     + (lookupUrl.port() == -1 ? "" : ":" + QString::number(lookupUrl.port())), trigger, hostChanged)) {
+
+                // a network address lookup clears the previous lookup since we don't expect to re-attempt it
+                _previousLookup.clear();
 
                 // If the host changed then we have already saved to history
                 if (hostChanged) {
@@ -165,10 +174,16 @@ bool AddressManager::handleUrl(const QUrl& lookupUrl, LookupTrigger trigger) {
                 // we may have a path that defines a relative viewpoint - if so we should jump to that now
                 handlePath(path, trigger);
             } else if (handleDomainID(lookupUrl.host())){
+                // store this domain ID as the previous lookup in case we're failing to connect and want to refresh API info
+                _previousLookup = lookupUrl;
+
                 // no place name - this is probably a domain ID
                 // try to look up the domain ID on the metaverse API
                 attemptDomainIDLookup(lookupUrl.host(), lookupUrl.path(), trigger);
             } else {
+                // store this place name as the previous lookup in case we fail to connect and want to refresh API info
+                _previousLookup = lookupUrl;
+
                 // wasn't an address - lookup the place name
                 // we may have a path that defines a relative viewpoint - pass that through the lookup so we can go to it after
                 attemptPlaceNameLookup(lookupUrl.host(), lookupUrl.path(), trigger);
@@ -180,9 +195,13 @@ bool AddressManager::handleUrl(const QUrl& lookupUrl, LookupTrigger trigger) {
     } else if (lookupUrl.toString().startsWith('/')) {
         qCDebug(networking) << "Going to relative path" << lookupUrl.path();
 
+        // a path lookup clears the previous lookup since we don't expect to re-attempt it
+        _previousLookup.clear();
+
         // if this is a relative path then handle it as a relative viewpoint
         handlePath(lookupUrl.path(), trigger, true);
         emit lookupResultsFinished();
+
         return true;
     }
 
@@ -276,7 +295,7 @@ void AddressManager::goToAddressFromObject(const QVariantMap& dataObject, const
 
                     qCDebug(networking) << "Possible domain change required to connect to" << domainHostname
                         << "on" << domainPort;
-                    emit possibleDomainChangeRequired(domainHostname, domainPort);
+                    emit possibleDomainChangeRequired(domainHostname, domainPort, domainID);
                 } else {
                     QString iceServerAddress = domainObject[DOMAIN_ICE_SERVER_ADDRESS_KEY].toString();
 
@@ -315,7 +334,10 @@ void AddressManager::goToAddressFromObject(const QVariantMap& dataObject, const
                 QString overridePath = reply.property(OVERRIDE_PATH_KEY).toString();
 
                 if (!overridePath.isEmpty()) {
-                    handlePath(overridePath, trigger);
+                    // make sure we don't re-handle an overriden path if this was a refresh of info from API
+                    if (trigger != LookupTrigger::AttemptedRefresh) {
+                        handlePath(overridePath, trigger);
+                    }
                 } else {
                     // take the path that came back
                     const QString PLACE_PATH_KEY = "path";
@@ -362,7 +384,7 @@ void AddressManager::handleAPIError(QNetworkReply& errorReply) {
 
     if (errorReply.error() == QNetworkReply::ContentNotFoundError) {
         // if this is a lookup that has no result, don't keep re-trying it
-        //_previousLookup.clear();
+        _previousLookup.clear();
 
         emit lookupResultIsNotFound();
     }
@@ -598,7 +620,7 @@ bool AddressManager::setDomainInfo(const QString& hostname, quint16 port, Lookup
 
     DependencyManager::get<NodeList>()->flagTimeForConnectionStep(LimitedNodeList::ConnectionStep::HandleAddress);
 
-    emit possibleDomainChangeRequired(hostname, port);
+    emit possibleDomainChangeRequired(hostname, port, QUuid());
 
     return hostChanged;
 }
@@ -618,6 +640,13 @@ void AddressManager::goToUser(const QString& username) {
                                               QByteArray(), nullptr, requestParams);
 }
 
+void AddressManager::refreshPreviousLookup() {
+    // if we have a non-empty previous lookup, fire it again now (but don't re-store it in the history)
+    if (!_previousLookup.isEmpty()) {
+        handleUrl(_previousLookup, LookupTrigger::AttemptedRefresh);
+    }
+}
+
 void AddressManager::copyAddress() {
     QApplication::clipboard()->setText(currentAddress().toString());
 }
@@ -629,7 +658,10 @@ void AddressManager::copyPath() {
 void AddressManager::addCurrentAddressToHistory(LookupTrigger trigger) {
 
     // if we're cold starting and this is called for the first address (from settings) we don't do anything
-    if (trigger != LookupTrigger::StartupFromSettings && trigger != LookupTrigger::DomainPathResponse) {
+    if (trigger != LookupTrigger::StartupFromSettings
+        && trigger != LookupTrigger::DomainPathResponse
+        && trigger != LookupTrigger::AttemptedRefresh) {
+
         if (trigger == LookupTrigger::Back) {
             // we're about to push to the forward stack
             // if it's currently empty emit our signal to say that going forward is now possible
diff --git a/libraries/networking/src/AddressManager.h b/libraries/networking/src/AddressManager.h
index 643924ff5c..a3aaee3ba2 100644
--- a/libraries/networking/src/AddressManager.h
+++ b/libraries/networking/src/AddressManager.h
@@ -48,7 +48,8 @@ public:
         Forward,
         StartupFromSettings,
         DomainPathResponse,
-        Internal
+        Internal,
+        AttemptedRefresh
     };
 
     bool isConnected();
@@ -89,6 +90,8 @@ public slots:
 
     void goToUser(const QString& username);
 
+    void refreshPreviousLookup();
+
     void storeCurrentAddress();
 
     void copyAddress();
@@ -99,7 +102,7 @@ signals:
     void lookupResultIsOffline();
     void lookupResultIsNotFound();
 
-    void possibleDomainChangeRequired(const QString& newHostname, quint16 newPort);
+    void possibleDomainChangeRequired(const QString& newHostname, quint16 newPort, const QUuid& domainID);
     void possibleDomainChangeRequiredViaICEForID(const QString& iceServerHostname, const QUuid& domainID);
 
     void locationChangeRequired(const glm::vec3& newPosition,
@@ -152,6 +155,8 @@ private:
     quint64 _lastBackPush = 0;
 
     QString _newHostLookupPath;
+    
+    QUrl _previousLookup;
 };
 
 #endif // hifi_AddressManager_h
diff --git a/libraries/networking/src/DomainHandler.cpp b/libraries/networking/src/DomainHandler.cpp
index 4f85296f03..6880b7a329 100644
--- a/libraries/networking/src/DomainHandler.cpp
+++ b/libraries/networking/src/DomainHandler.cpp
@@ -14,6 +14,7 @@
 #include <QtCore/QJsonDocument>
 #include <QtCore/QDataStream>
 
+#include "AddressManager.h"
 #include "Assignment.h"
 #include "HifiSockAddr.h"
 #include "NodeList.h"
@@ -28,17 +29,10 @@
 
 DomainHandler::DomainHandler(QObject* parent) :
     QObject(parent),
-    _uuid(),
     _sockAddr(HifiSockAddr(QHostAddress::Null, DEFAULT_DOMAIN_SERVER_PORT)),
-    _assignmentUUID(),
-    _connectionToken(),
-    _iceDomainID(),
-    _iceClientID(),
-    _iceServerSockAddr(),
     _icePeer(this),
-    _isConnected(false),
-    _settingsObject(),
-    _settingsTimer(this)
+    _settingsTimer(this),
+    _apiRefreshTimer(this)
 {
     _sockAddr.setObjectName("DomainServer");
 
@@ -49,6 +43,16 @@ DomainHandler::DomainHandler(QObject* parent) :
     static const int DOMAIN_SETTINGS_TIMEOUT_MS = 5000;
     _settingsTimer.setInterval(DOMAIN_SETTINGS_TIMEOUT_MS);
     connect(&_settingsTimer, &QTimer::timeout, this, &DomainHandler::settingsReceiveFail);
+
+    // setup the API refresh timer for auto connection information refresh from API when failing to connect
+    const int API_REFRESH_TIMEOUT_MSEC = 2500;
+    _apiRefreshTimer.setInterval(API_REFRESH_TIMEOUT_MSEC);
+
+    auto addressManager = DependencyManager::get<AddressManager>();
+    connect(&_apiRefreshTimer, &QTimer::timeout, addressManager.data(), &AddressManager::refreshPreviousLookup);
+
+    // stop the refresh timer if we connect to a domain
+    connect(this, &DomainHandler::connectedToDomain, &_apiRefreshTimer, &QTimer::stop);
 }
 
 void DomainHandler::disconnect() {
@@ -93,10 +97,14 @@ void DomainHandler::softReset() {
     
     clearSettings();
 
+    _domainConnectionRefusals.clear();
     _connectionDenialsSinceKeypairRegen = 0;
 
     // cancel the failure timeout for any pending requests for settings
     QMetaObject::invokeMethod(&_settingsTimer, "stop");
+
+    // restart the API refresh timer in case we fail to connect and need to refresh information
+    QMetaObject::invokeMethod(&_apiRefreshTimer, "start");
 }
 
 void DomainHandler::hardReset() {
@@ -105,7 +113,7 @@ void DomainHandler::hardReset() {
     softReset();
 
     qCDebug(networking) << "Hard reset in NodeList DomainHandler.";
-    _iceDomainID = QUuid();
+    _pendingDomainID = QUuid();
     _iceServerSockAddr = HifiSockAddr();
     _hostname = QString();
     _sockAddr.clear();
@@ -139,7 +147,9 @@ void DomainHandler::setUUID(const QUuid& uuid) {
     }
 }
 
-void DomainHandler::setHostnameAndPort(const QString& hostname, quint16 port) {
+void DomainHandler::setSocketAndID(const QString& hostname, quint16 port, const QUuid& domainID) {
+
+    _pendingDomainID = domainID;
 
     if (hostname != _hostname || _sockAddr.getPort() != port) {
         // re-set the domain info so that auth information is reloaded
@@ -149,9 +159,6 @@ void DomainHandler::setHostnameAndPort(const QString& hostname, quint16 port) {
             // set the new hostname
             _hostname = hostname;
 
-            // FIXME - is this the right place???
-            _domainConnectionRefusals.clear();
-
             qCDebug(networking) << "Updated domain hostname to" << _hostname;
 
             // re-set the sock addr to null and fire off a lookup of the IP address for this domain-server's hostname
@@ -174,14 +181,15 @@ void DomainHandler::setHostnameAndPort(const QString& hostname, quint16 port) {
 }
 
 void DomainHandler::setIceServerHostnameAndID(const QString& iceServerHostname, const QUuid& id) {
-    if (id != _uuid) {
+
+    if (_iceServerSockAddr.getAddress().toString() != iceServerHostname || id != _pendingDomainID) {
         // re-set the domain info to connect to new domain
         hardReset();
         
         // refresh our ICE client UUID to something new
         _iceClientID = QUuid::createUuid();
         
-        _iceDomainID = id;
+        _pendingDomainID = id;
 
         HifiSockAddr* replaceableSockAddr = &_iceServerSockAddr;
         replaceableSockAddr->~HifiSockAddr();
@@ -255,6 +263,7 @@ void DomainHandler::setIsConnected(bool isConnected) {
 
             // we've connected to new domain - time to ask it for global settings
             requestDomainSettings();
+
         } else {
             emit disconnectedFromDomain();
         }
@@ -305,6 +314,9 @@ void DomainHandler::processICEPingReplyPacket(QSharedPointer<ReceivedMessage> me
     qCDebug(networking) << "Received reply from domain-server on" << senderSockAddr;
 
     if (getIP().isNull()) {
+        // we're hearing back from this domain-server, no need to refresh API information
+        _apiRefreshTimer.stop();
+
         // for now we're unsafely assuming this came back from the domain
         if (senderSockAddr == _icePeer.getLocalSocket()) {
             qCDebug(networking) << "Connecting to domain using local socket";
@@ -333,17 +345,20 @@ void DomainHandler::processDTLSRequirementPacket(QSharedPointer<ReceivedMessage>
 void DomainHandler::processICEResponsePacket(QSharedPointer<ReceivedMessage> message) {
     if (_icePeer.hasSockets()) {
         qDebug() << "Received an ICE peer packet for domain-server but we already have sockets. Not processing.";
-        // bail on processing this packet if our ice peer doesn't have sockets
+        // bail on processing this packet if our ice peer already has sockets
         return;
     }
 
+    // start or restart the API refresh timer now that we have new information
+    _apiRefreshTimer.start();
+
     QDataStream iceResponseStream(message->getMessage());
 
     iceResponseStream >> _icePeer;
 
     DependencyManager::get<NodeList>()->flagTimeForConnectionStep(LimitedNodeList::ConnectionStep::ReceiveDSPeerInformation);
 
-    if (_icePeer.getUUID() != _iceDomainID) {
+    if (_icePeer.getUUID() != _pendingDomainID) {
         qCDebug(networking) << "Received a network peer with ID that does not match current domain. Will not attempt connection.";
         _icePeer.reset();
     } else {
@@ -373,6 +388,9 @@ bool DomainHandler::reasonSuggestsLogin(ConnectionRefusedReason reasonCode) {
 }
 
 void DomainHandler::processDomainServerConnectionDeniedPacket(QSharedPointer<ReceivedMessage> message) {
+    // we're hearing from this domain-server, don't need to refresh API info
+    _apiRefreshTimer.stop();
+
     // Read deny reason from packet
     uint8_t reasonCodeWire;
 
diff --git a/libraries/networking/src/DomainHandler.h b/libraries/networking/src/DomainHandler.h
index bcee7668d1..1328174e87 100644
--- a/libraries/networking/src/DomainHandler.h
+++ b/libraries/networking/src/DomainHandler.h
@@ -58,8 +58,8 @@ public:
     
     const QUuid& getAssignmentUUID() const { return _assignmentUUID; }
     void setAssignmentUUID(const QUuid& assignmentUUID) { _assignmentUUID = assignmentUUID; }
-    
-    const QUuid& getICEDomainID() const { return _iceDomainID; }
+
+    const QUuid& getPendingDomainID() const { return _pendingDomainID; }
 
     const QUuid& getICEClientID() const { return _iceClientID; }
 
@@ -75,7 +75,6 @@ public:
     bool hasSettings() const { return !_settingsObject.isEmpty(); }
     void requestDomainSettings();
     const QJsonObject& getSettingsObject() const { return _settingsObject; }
-
    
     void setPendingPath(const QString& pendingPath) { _pendingPath = pendingPath; }
     const QString& getPendingPath() { return _pendingPath; }
@@ -94,7 +93,7 @@ public:
     };
 
 public slots:
-    void setHostnameAndPort(const QString& hostname, quint16 port = DEFAULT_DOMAIN_SERVER_PORT);
+    void setSocketAndID(const QString& hostname, quint16 port = DEFAULT_DOMAIN_SERVER_PORT, const QUuid& id = QUuid());
     void setIceServerHostnameAndID(const QString& iceServerHostname, const QUuid& id);
 
     void processSettingsPacketList(QSharedPointer<ReceivedMessage> packetList);
@@ -136,11 +135,11 @@ private:
     HifiSockAddr _sockAddr;
     QUuid _assignmentUUID;
     QUuid _connectionToken;
-    QUuid _iceDomainID;
+    QUuid _pendingDomainID; // ID of domain being connected to, via ICE or direct connection
     QUuid _iceClientID;
     HifiSockAddr _iceServerSockAddr;
     NetworkPeer _icePeer;
-    bool _isConnected;
+    bool _isConnected { false };
     QJsonObject _settingsObject;
     QString _pendingPath;
     QTimer _settingsTimer;
@@ -148,6 +147,8 @@ private:
     QStringList _domainConnectionRefusals;
     bool _hasCheckedForAccessToken { false };
     int _connectionDenialsSinceKeypairRegen { 0 };
+
+    QTimer _apiRefreshTimer;
 };
 
 #endif // hifi_DomainHandler_h
diff --git a/libraries/networking/src/NLPacket.cpp b/libraries/networking/src/NLPacket.cpp
index 34a159ae6c..a11dd69753 100644
--- a/libraries/networking/src/NLPacket.cpp
+++ b/libraries/networking/src/NLPacket.cpp
@@ -184,6 +184,11 @@ void NLPacket::setType(PacketType type) {
     writeTypeAndVersion();
 }
 
+void NLPacket::setVersion(PacketVersion version) {
+    _version = version;
+    writeTypeAndVersion();
+}
+
 void NLPacket::readType() {
     _type = NLPacket::typeInHeader(*this);
 }
diff --git a/libraries/networking/src/NLPacket.h b/libraries/networking/src/NLPacket.h
index f49f8498a5..33de262dfb 100644
--- a/libraries/networking/src/NLPacket.h
+++ b/libraries/networking/src/NLPacket.h
@@ -65,6 +65,7 @@ public:
     void setType(PacketType type);
     
     PacketVersion getVersion() const { return _version; }
+    void setVersion(PacketVersion version);
 
     const QUuid& getSourceID() const { return _sourceID; }
     
diff --git a/libraries/networking/src/NodeList.cpp b/libraries/networking/src/NodeList.cpp
index 3bcea740e7..11b5f5469a 100644
--- a/libraries/networking/src/NodeList.cpp
+++ b/libraries/networking/src/NodeList.cpp
@@ -50,7 +50,7 @@ NodeList::NodeList(char newOwnerType, unsigned short socketListenPort, unsigned
 
     // handle domain change signals from AddressManager
     connect(addressManager.data(), &AddressManager::possibleDomainChangeRequired,
-            &_domainHandler, &DomainHandler::setHostnameAndPort);
+            &_domainHandler, &DomainHandler::setSocketAndID);
 
     connect(addressManager.data(), &AddressManager::possibleDomainChangeRequiredViaICEForID,
             &_domainHandler, &DomainHandler::setIceServerHostnameAndID);
@@ -250,7 +250,6 @@ void NodeList::sendDomainServerCheckIn() {
         qCDebug(networking) << "Waiting for ICE discovered domain-server socket. Will not send domain-server check in.";
         handleICEConnectionToDomainServer();
     } else if (!_domainHandler.getIP().isNull()) {
-        bool isUsingDTLS = false;
 
         PacketType domainPacketType = !_domainHandler.isConnected()
             ? PacketType::DomainConnectRequest : PacketType::DomainListRequest;
@@ -292,12 +291,18 @@ void NodeList::sendDomainServerCheckIn() {
             return;
         }
 
-        auto packetVersion = (domainPacketType == PacketType::DomainConnectRequest) ? _domainConnectRequestVersion : 0;
-        auto domainPacket = NLPacket::create(domainPacketType, -1, false, false, packetVersion);
+        auto domainPacket = NLPacket::create(domainPacketType);
         
         QDataStream packetStream(domainPacket.get());
 
         if (domainPacketType == PacketType::DomainConnectRequest) {
+
+#if (PR_BUILD || DEV_BUILD)
+            if (_shouldSendNewerVersion) {
+                domainPacket->setVersion(versionForPacketType(domainPacketType) + 1);
+            }
+#endif
+
             QUuid connectUUID;
 
             if (!_domainHandler.getAssignmentUUID().isNull()) {
@@ -315,18 +320,14 @@ void NodeList::sendDomainServerCheckIn() {
             packetStream << connectUUID;
 
             // include the protocol version signature in our connect request
-            if (_domainConnectRequestVersion >= static_cast<PacketVersion>(DomainConnectRequestVersion::HasProtocolVersions)) {
-                QByteArray protocolVersionSig = protocolVersionsSignature();
-                packetStream.writeBytes(protocolVersionSig.constData(), protocolVersionSig.size());
-            }
+            QByteArray protocolVersionSig = protocolVersionsSignature();
+            packetStream.writeBytes(protocolVersionSig.constData(), protocolVersionSig.size());
         }
 
         // pack our data to send to the domain-server including
         // the hostname information (so the domain-server can see which place name we came in on)
         packetStream << _ownerType << _publicSockAddr << _localSockAddr << _nodeTypesOfInterest.toList();
-        if (_domainConnectRequestVersion >= static_cast<PacketVersion>(DomainConnectRequestVersion::HasHostname)) {
-            packetStream << DependencyManager::get<AddressManager>()->getPlaceName();
-        }
+        packetStream << DependencyManager::get<AddressManager>()->getPlaceName();
 
         if (!_domainHandler.isConnected()) {
             DataServerAccountInfo& accountInfo = accountManager->getAccountInfo();
@@ -341,9 +342,7 @@ void NodeList::sendDomainServerCheckIn() {
 
         flagTimeForConnectionStep(LimitedNodeList::ConnectionStep::SendDSCheckIn);
 
-        if (!isUsingDTLS) {
-            sendPacket(std::move(domainPacket), _domainHandler.getSockAddr());
-        }
+        sendPacket(std::move(domainPacket), _domainHandler.getSockAddr());
 
         if (_numNoReplyDomainCheckIns >= MAX_SILENT_DOMAIN_SERVER_CHECK_INS) {
             // we haven't heard back from DS in MAX_SILENT_DOMAIN_SERVER_CHECK_INS
@@ -462,7 +461,7 @@ void NodeList::handleICEConnectionToDomainServer() {
 
         LimitedNodeList::sendPeerQueryToIceServer(_domainHandler.getICEServerSockAddr(),
                                                   _domainHandler.getICEClientID(),
-                                                  _domainHandler.getICEDomainID());
+                                                  _domainHandler.getPendingDomainID());
     }
 }
 
@@ -475,7 +474,7 @@ void NodeList::pingPunchForDomainServer() {
 
         if (_domainHandler.getICEPeer().getConnectionAttempts() == 0) {
             qCDebug(networking) << "Sending ping packets to establish connectivity with domain-server with ID"
-                << uuidStringWithoutCurlyBraces(_domainHandler.getICEDomainID());
+                << uuidStringWithoutCurlyBraces(_domainHandler.getPendingDomainID());
         } else {
             if (_domainHandler.getICEPeer().getConnectionAttempts() % NUM_DOMAIN_SERVER_PINGS_BEFORE_RESET == 0) {
                 // if we have then nullify the domain handler's network peer and send a fresh ICE heartbeat
diff --git a/libraries/networking/src/NodeList.h b/libraries/networking/src/NodeList.h
index b269554e77..3fbc86c736 100644
--- a/libraries/networking/src/NodeList.h
+++ b/libraries/networking/src/NodeList.h
@@ -68,9 +68,6 @@ public:
     
     void setIsShuttingDown(bool isShuttingDown) { _isShuttingDown = isShuttingDown; }
 
-    /// downgrades the DomainConnnectRequest PacketVersion to attempt to probe for older domain servers
-    void downgradeDomainServerCheckInVersion() { _domainConnectRequestVersion--; }
-
 public slots:
     void reset();
     void sendDomainServerCheckIn();
@@ -88,8 +85,9 @@ public slots:
 
     void processICEPingPacket(QSharedPointer<ReceivedMessage> message);
 
-    void resetDomainServerCheckInVersion() 
-            { _domainConnectRequestVersion = versionForPacketType(PacketType::DomainConnectRequest); }
+#if (PR_BUILD || DEV_BUILD)
+    void toggleSendNewerDSConnectVersion(bool shouldSendNewerVersion) { _shouldSendNewerVersion = shouldSendNewerVersion; }
+#endif
 
 signals:
     void limitOfSilentDomainCheckInsReached();
@@ -105,6 +103,7 @@ private slots:
     void pingPunchForDomainServer();
     
     void sendKeepAlivePings();
+    
 private:
     NodeList() : LimitedNodeList(0, 0) { assert(false); } // Not implemented, needed for DependencyManager templates compile
     NodeList(char ownerType, unsigned short socketListenPort = 0, unsigned short dtlsListenPort = 0);
@@ -130,7 +129,9 @@ private:
     bool _isShuttingDown { false };
     QTimer _keepAlivePingTimer;
 
-    PacketVersion _domainConnectRequestVersion = versionForPacketType(PacketType::DomainConnectRequest);
+#if (PR_BUILD || DEV_BUILD)
+    bool _shouldSendNewerVersion { false };
+#endif
 };
 
 #endif // hifi_NodeList_h
diff --git a/libraries/shared/src/GenericQueueThread.h b/libraries/shared/src/GenericQueueThread.h
index 28fcdb0ed6..7c1bdccaa7 100644
--- a/libraries/shared/src/GenericQueueThread.h
+++ b/libraries/shared/src/GenericQueueThread.h
@@ -12,9 +12,10 @@
 
 #include <stdint.h>
 
-#include <QQueue>
-#include <QMutex>
-#include <QWaitCondition>
+#include <QtCore/QElapsedTimer>
+#include <QtCore/QMutex>
+#include <QtCore/QQueue>
+#include <QtCore/QWaitCondition>
 
 #include "GenericThread.h"
 #include "NumericalConstants.h"
@@ -35,6 +36,25 @@ public:
         _hasItems.wakeAll();
     }
 
+    void waitIdle(uint32_t maxWaitMs = UINT32_MAX) {
+        QElapsedTimer timer;
+        timer.start();
+
+        // FIXME this will work as long as the thread doing the wait
+        // is the only thread which can add work to the queue.  
+        // It would be better if instead we had a queue empty condition to wait on
+        // that would ensure that we get woken as soon as we're idle the very 
+        // first time the queue was empty.
+        while (timer.elapsed() < maxWaitMs) {
+            lock();
+            if (!_items.size()) {
+                unlock();
+                return;
+            }
+            unlock();
+        }
+    }
+
 protected:
     virtual void queueItemInternal(const T& t) {
         _items.push_back(t);
@@ -44,6 +64,7 @@ protected:
         return MSECS_PER_SECOND;
     }
 
+
     virtual bool process() {
         lock();
         if (!_items.size()) {