diff --git a/source/base/CMakeLists.txt b/source/base/CMakeLists.txt
index e813e45..e77d9ff 100644
--- a/source/base/CMakeLists.txt
+++ b/source/base/CMakeLists.txt
@@ -18,7 +18,6 @@ SET (star_base_HEADERS
     StarMixer.hpp
     StarPackedAssetSource.hpp
     StarRootBase.hpp
-    StarVersion.hpp
     StarVersionOptionParser.hpp
     StarWorldGeometry.hpp
     scripting/StarImageLuaBindings.hpp
@@ -40,8 +39,7 @@ SET (star_base_SOURCES
     scripting/StarImageLuaBindings.cpp
   )
 
-CONFIGURE_FILE (StarVersion.cpp.in ${CMAKE_CURRENT_BINARY_DIR}/StarVersion.cpp)
-ADD_LIBRARY (star_base OBJECT ${star_base_SOURCES} ${star_base_HEADERS} ${CMAKE_CURRENT_BINARY_DIR}/StarVersion.cpp)
+ADD_LIBRARY (star_base OBJECT ${star_base_SOURCES} ${star_base_HEADERS})
 
 IF(STAR_PRECOMPILED_HEADERS)
   TARGET_PRECOMPILE_HEADERS (star_base REUSE_FROM star_core)
diff --git a/source/core/CMakeLists.txt b/source/core/CMakeLists.txt
index bb8bd22..2f0c858 100644
--- a/source/core/CMakeLists.txt
+++ b/source/core/CMakeLists.txt
@@ -124,6 +124,7 @@ SET (star_core_HEADERS
     StarUnicode.hpp
     StarUuid.hpp
     StarVector.hpp
+    StarVersion.hpp
     StarVlqEncoding.hpp
     StarWeightedPool.hpp
     StarWorkerPool.hpp
@@ -164,6 +165,7 @@ SET (star_core_SOURCES
     StarLua.cpp
     StarLuaConverters.cpp
     StarMemory.cpp
+    StarNetCompatibility.cpp
     StarNetElement.cpp
     StarNetElementBasicFields.cpp
     StarNetElementGroup.cpp
@@ -219,7 +221,8 @@ ELSEIF (STAR_SYSTEM_FAMILY_WINDOWS)
 
 ENDIF ()
 
-ADD_LIBRARY (star_core OBJECT ${star_core_SOURCES} ${star_core_HEADERS})
+CONFIGURE_FILE (StarVersion.cpp.in ${CMAKE_CURRENT_BINARY_DIR}/StarVersion.cpp)
+ADD_LIBRARY (star_core OBJECT ${star_core_SOURCES} ${star_core_HEADERS} ${CMAKE_CURRENT_BINARY_DIR}/StarVersion.cpp)
 
 IF(STAR_PRECOMPILED_HEADERS)
   TARGET_PRECOMPILE_HEADERS (star_core PUBLIC StarPch.hpp)
diff --git a/source/core/StarDataStream.cpp b/source/core/StarDataStream.cpp
index 1224f54..3a4ed0c 100644
--- a/source/core/StarDataStream.cpp
+++ b/source/core/StarDataStream.cpp
@@ -36,10 +36,7 @@ void DataStream::setStreamCompatibilityVersion(unsigned streamCompatibilityVersi
 }
 
 void DataStream::setStreamCompatibilityVersion(NetCompatibilityRules const& rules) {
-  if (rules.isLegacy)
-    m_streamCompatibilityVersion = 1;
-  else
-    m_streamCompatibilityVersion = CurrentStreamVersion;
+  m_streamCompatibilityVersion = rules.version();
 }
 
 ByteArray DataStream::readBytes(size_t len) {
diff --git a/source/core/StarNetCompatibility.cpp b/source/core/StarNetCompatibility.cpp
new file mode 100644
index 0000000..fdd53fb
--- /dev/null
+++ b/source/core/StarNetCompatibility.cpp
@@ -0,0 +1,7 @@
+#include "StarNetCompatibility.hpp"
+
+namespace Star {
+
+VersionNumber const OpenProtocolVersion = 2;
+
+}
\ No newline at end of file
diff --git a/source/core/StarNetCompatibility.hpp b/source/core/StarNetCompatibility.hpp
index 730546e..4b950ab 100644
--- a/source/core/StarNetCompatibility.hpp
+++ b/source/core/StarNetCompatibility.hpp
@@ -1,40 +1,54 @@
 #pragma once
-#include "StarDataStream.hpp"
+#include "StarVersion.hpp"
+#include "StarHash.hpp"
 
 namespace Star {
 
+extern VersionNumber const OpenProtocolVersion;
 
-enum class NetCompatibilityFilter {
-  None = 0,
-  Old = 1,
-  New = 2
-};
+constexpr VersionNumber AnyVersion = 0xFFFFFFFF;
+constexpr VersionNumber LegacyVersion = 0;
 
-struct NetCompatibilityRules {
-  NetCompatibilityRules() = default;
+class NetCompatibilityRules {
+public:
+  NetCompatibilityRules();
   NetCompatibilityRules(uint64_t) = delete;
-  NetCompatibilityRules(bool legacy);
+  NetCompatibilityRules(VersionNumber version);
 
-  bool checkFilter(NetCompatibilityFilter const& filter) const;
+  VersionNumber version() const;
+  void setVersion(VersionNumber version);
+  bool isLegacy() const;
 
-  bool isLegacy = false;
+  bool operator==(NetCompatibilityRules const& a) const;
+
+private:
+  VersionNumber m_version = OpenProtocolVersion;
 };
 
-inline NetCompatibilityRules::NetCompatibilityRules(bool legacy) : isLegacy(legacy) {}
+inline NetCompatibilityRules::NetCompatibilityRules() : m_version(OpenProtocolVersion) {}
 
-inline bool NetCompatibilityRules::checkFilter(NetCompatibilityFilter const& filter) const {
-  if (filter == NetCompatibilityFilter::None)
-    return true;
-  else if (isLegacy)
-    return filter == NetCompatibilityFilter::Old;
-  else
-    return filter == NetCompatibilityFilter::New;
+inline NetCompatibilityRules::NetCompatibilityRules(VersionNumber v) : m_version(v) {}
+
+inline VersionNumber NetCompatibilityRules::version() const {
+  return m_version;
+}
+
+inline void NetCompatibilityRules::setVersion(VersionNumber version) {
+  m_version = version;
+}
+
+inline bool NetCompatibilityRules::isLegacy() const {
+  return m_version == LegacyVersion;
+}
+
+inline bool NetCompatibilityRules::operator==(NetCompatibilityRules const& a) const {
+  return m_version == a.m_version;
 }
 
 template <>
 struct hash<NetCompatibilityRules> {
   size_t operator()(NetCompatibilityRules const& s) const {
-    return s.isLegacy;
+    return s.version();
   }
 };
 
diff --git a/source/core/StarNetElement.hpp b/source/core/StarNetElement.hpp
index 393dd3d..7d73b85 100644
--- a/source/core/StarNetElement.hpp
+++ b/source/core/StarNetElement.hpp
@@ -55,23 +55,25 @@ public:
   // received even if no deltas are produced, so no extrapolation takes place.
   virtual void blankNetDelta(float interpolationTime);
 
-  NetCompatibilityFilter netCompatibilityFilter() const;
-  void setNetCompatibilityFilter(NetCompatibilityFilter netFilter);
+  VersionNumber compatibilityVersion() const;
+  void setCompatibilityVersion(VersionNumber version);
   bool checkWithRules(NetCompatibilityRules const& rules) const;
 private:
-  NetCompatibilityFilter m_netCompatibilityFilter = NetCompatibilityFilter::None;
+  VersionNumber m_netCompatibilityVersion = AnyVersion;
 };
 
-inline NetCompatibilityFilter NetElement::netCompatibilityFilter() const {
-  return m_netCompatibilityFilter;
+inline VersionNumber NetElement::compatibilityVersion() const {
+  return m_netCompatibilityVersion;
 }
 
-inline void NetElement::setNetCompatibilityFilter(NetCompatibilityFilter netFilter) {
-  m_netCompatibilityFilter = netFilter;
+inline void NetElement::setCompatibilityVersion(VersionNumber version) {
+  m_netCompatibilityVersion = version;
 }
 
 inline bool NetElement::checkWithRules(NetCompatibilityRules const& rules) const {
-  return rules.checkFilter(m_netCompatibilityFilter);
+  if (m_netCompatibilityVersion != AnyVersion)
+    return rules.version() >= m_netCompatibilityVersion;
+  return true;
 }
 
 }
diff --git a/source/base/StarVersion.cpp.in b/source/core/StarVersion.cpp.in
similarity index 100%
rename from source/base/StarVersion.cpp.in
rename to source/core/StarVersion.cpp.in
diff --git a/source/base/StarVersion.hpp b/source/core/StarVersion.hpp
similarity index 100%
rename from source/base/StarVersion.hpp
rename to source/core/StarVersion.hpp
diff --git a/source/game/StarNetPackets.cpp b/source/game/StarNetPackets.cpp
index dd80d76..b8605ed 100644
--- a/source/game/StarNetPackets.cpp
+++ b/source/game/StarNetPackets.cpp
@@ -5,7 +5,6 @@
 namespace Star {
 
 VersionNumber const StarProtocolVersion = 747;
-VersionNumber const OpenProtocolVersion = 1;
 
 EnumMap<PacketType> const PacketTypeNames{
   {PacketType::ProtocolRequest, "ProtocolRequest"},
diff --git a/source/game/StarNetPackets.hpp b/source/game/StarNetPackets.hpp
index e68a045..87a01cf 100644
--- a/source/game/StarNetPackets.hpp
+++ b/source/game/StarNetPackets.hpp
@@ -23,7 +23,6 @@ STAR_STRUCT(Packet);
 STAR_EXCEPTION(StarPacketException, IOException);
 
 extern VersionNumber const StarProtocolVersion;
-extern VersionNumber const OpenProtocolVersion;
 
 // Packet types sent between the client and server over a NetSocket.  Does not
 // correspond to actual packets, simply logical portions of NetSocket data.
diff --git a/source/game/StarStatusController.cpp b/source/game/StarStatusController.cpp
index a2a5e9c..325fc17 100644
--- a/source/game/StarStatusController.cpp
+++ b/source/game/StarStatusController.cpp
@@ -21,15 +21,15 @@ StatusController::StatusController(Json const& config) : m_statCollection(config
   m_statusProperties.reset(config.getObject("statusProperties", {}));
   m_statusProperties.setOverrides(
     [&](DataStream& ds, NetCompatibilityRules rules) {
-      if (rules.isLegacy) ds << m_statusProperties.baseMap();
+      if (rules.version() <= 1) ds << m_statusProperties.baseMap();
       else m_statusProperties.NetElementHashMap<String, Json>::netStore(ds, rules);
     },
     [&](DataStream& ds, NetCompatibilityRules rules) {
-      if (rules.isLegacy) m_statusProperties.reset(ds.read<JsonObject>());
+      if (rules.version() <= 1) m_statusProperties.reset(ds.read<JsonObject>());
       else m_statusProperties.NetElementHashMap<String, Json>::netLoad(ds, rules);
     },
     [&](DataStream& ds, uint64_t fromVersion, NetCompatibilityRules rules) {
-      if (rules.isLegacy) {
+      if (rules.version() <= 1) {
         if (m_statusProperties.shouldWriteNetDelta(fromVersion, rules)) {
           ds << m_statusProperties.baseMap();
           return true;
@@ -39,7 +39,7 @@ StatusController::StatusController(Json const& config) : m_statCollection(config
       return m_statusProperties.NetElementHashMap<String, Json>::writeNetDelta(ds, fromVersion, rules);
     },
     [&](DataStream& ds, float interp, NetCompatibilityRules rules) {
-      if (rules.isLegacy) m_statusProperties.reset(ds.read<JsonObject>());
+      if (rules.version() <= 1) m_statusProperties.reset(ds.read<JsonObject>());
       else m_statusProperties.NetElementHashMap<String, Json>::readNetDelta(ds, interp, rules);
     }
   );
diff --git a/source/game/StarUniverseClient.cpp b/source/game/StarUniverseClient.cpp
index 023140c..6038901 100644
--- a/source/game/StarUniverseClient.cpp
+++ b/source/game/StarUniverseClient.cpp
@@ -94,20 +94,27 @@ Maybe<String> UniverseClient::connect(UniverseConnection connection, bool allowA
   else if (!protocolResponsePacket->allowed)
     return String(strf("Join failed! Server does not support connections with protocol version {}", StarProtocolVersion));
 
+  NetCompatibilityRules compatibilityRules;
+  compatibilityRules.setVersion(LegacyVersion);
   bool legacyServer = protocolResponsePacket->compressionMode() != PacketCompressionMode::Enabled;
   if (!legacyServer) {
-    if (auto compressedSocket = as<CompressedPacketSocket>(&connection.packetSocket())) {
-      if (protocolResponsePacket->info) {
-        auto compressionName = protocolResponsePacket->info.getString("compression", "None");
+    auto compressedSocket = as<CompressedPacketSocket>(&connection.packetSocket());
+    if (protocolResponsePacket->info) {
+      compatibilityRules.setVersion(protocolResponsePacket->info.getUInt("openProtocolVersion", 1));
+      auto compressionName = protocolResponsePacket->info.getString("compression", "None");
+      if (compressedSocket) {
         auto compressionMode = NetCompressionModeNames.maybeLeft(compressionName);
         if (!compressionMode)
           return String(strf("Join failed! Unknown net stream connection type '{}'", compressionName));
 
         Logger::info("UniverseClient: Using '{}' network stream compression", NetCompressionModeNames.getRight(*compressionMode));
         compressedSocket->setCompressionStreamEnabled(compressionMode == NetCompressionMode::Zstd);
-      } else {
+      }
+    } else {
+      compatibilityRules.setVersion(1); // A version of 1 is OpenStarbound prior to the NetElement compatibility stuff
+      if (compressedSocket) {
         Logger::info("UniverseClient: Defaulting to Zstd network stream compression (older server version)");
-        compressedSocket->setCompressionStreamEnabled(true);// old OpenSB server version always expects it!
+        compressedSocket->setCompressionStreamEnabled(true);
       }
     }
   }
@@ -115,7 +122,10 @@ Maybe<String> UniverseClient::connect(UniverseConnection connection, bool allowA
   auto clientConnect = make_shared<ClientConnectPacket>(Root::singleton().assets()->digest(), allowAssetsMismatch, m_mainPlayer->uuid(), m_mainPlayer->name(),
       m_mainPlayer->species(), m_playerStorage->loadShipData(m_mainPlayer->uuid()), m_mainPlayer->shipUpgrades(),
       m_mainPlayer->log()->introComplete(), account);
-  clientConnect->info = JsonObject{ {"brand", "OpenStarbound"} };
+  clientConnect->info = JsonObject{
+    {"brand", "OpenStarbound"},
+    {"openProtocolVersion", OpenProtocolVersion }
+  };
   connection.pushSingle(std::move(clientConnect));
   connection.sendAll(timeout);
 
@@ -134,9 +144,6 @@ Maybe<String> UniverseClient::connect(UniverseConnection connection, bool allowA
     packet = connection.pullSingle();
   }
 
-  NetCompatibilityRules compatibilityRules;
-  compatibilityRules.isLegacy = legacyServer;
-
   if (auto success = as<ConnectSuccessPacket>(packet)) {
     m_universeClock = make_shared<Clock>();
     m_clientContext = make_shared<ClientContext>(success->serverUuid, m_mainPlayer->uuid());
diff --git a/source/game/StarUniverseServer.cpp b/source/game/StarUniverseServer.cpp
index 09cfdc8..6961ce4 100644
--- a/source/game/StarUniverseServer.cpp
+++ b/source/game/StarUniverseServer.cpp
@@ -1577,7 +1577,8 @@ void UniverseServer::acceptConnection(UniverseConnection connection, Maybe<HostA
     auto compressionMode = NetCompressionModeNames.maybeLeft(compressionName).value(NetCompressionMode::None);
     useCompressionStream = compressionMode == NetCompressionMode::Zstd;
     protocolResponse->info = JsonObject{
-      {"compression", NetCompressionModeNames.getRight(compressionMode)}
+      {"compression", NetCompressionModeNames.getRight(compressionMode)},
+      {"openProtocolVersion", OpenProtocolVersion}
     };
   }
   connection.pushSingle(protocolResponse);
@@ -1674,7 +1675,10 @@ void UniverseServer::acceptConnection(UniverseConnection connection, Maybe<HostA
   String connectionLog = strf("UniverseServer: Logged in account '{}' as player '{}' from address {}",
     accountString, clientConnect->playerName, remoteAddressString);
 
+  NetCompatibilityRules netRules(legacyClient ? LegacyVersion : 1);
   if (Json& info = clientConnect->info) {
+    if (auto openProtocolVersion = info.optUInt("openProtocolVersion"))
+      netRules.setVersion(*openProtocolVersion);
     if (Json brand = info.get("brand", "custom"))
       connectionLog += strf(" ({} client)", brand.toString());
     if (info.getBool("legacy", false))
@@ -1701,7 +1705,6 @@ void UniverseServer::acceptConnection(UniverseConnection connection, Maybe<HostA
   }
 
   ConnectionId clientId = m_clients.nextId();
-  NetCompatibilityRules netRules(legacyClient);
   auto clientContext = make_shared<ServerClientContext>(clientId, remoteAddress, netRules, clientConnect->playerUuid,
       clientConnect->playerName, clientConnect->playerSpecies, administrator, clientConnect->shipChunks);
   m_clients.add(clientId, clientContext);
diff --git a/source/game/StarWorldClient.cpp b/source/game/StarWorldClient.cpp
index aecb77a..b18127e 100644
--- a/source/game/StarWorldClient.cpp
+++ b/source/game/StarWorldClient.cpp
@@ -1230,7 +1230,7 @@ void WorldClient::update(float dt) {
 
   queueUpdatePackets(m_entityUpdateTimer.wrapTick(dt));
 
-  if ((!m_clientState.netCompatibilityRules().isLegacy && m_currentStep % 3 == 0) || m_pingTime.isNothing()) {
+  if ((!m_clientState.netCompatibilityRules().isLegacy() && m_currentStep % 3 == 0) || m_pingTime.isNothing()) {
     m_pingTime = Time::monotonicMilliseconds();
     m_outgoingPackets.append(make_shared<PingPacket>(*m_pingTime));
   }
diff --git a/source/game/StarWorldServer.cpp b/source/game/StarWorldServer.cpp
index a2df77b..fbc23a9 100644
--- a/source/game/StarWorldServer.cpp
+++ b/source/game/StarWorldServer.cpp
@@ -692,7 +692,6 @@ void WorldServer::update(float dt) {
     queueUpdatePackets(pair.first, sendRemoteUpdates);
   }
   m_netStateCache.clear();
-  m_legacyNetStateCache.clear();
 
   for (auto& pair : m_clientInfo)
     pair.second->pendingForward = false;
@@ -1872,7 +1871,7 @@ void WorldServer::queueUpdatePackets(ConnectionId clientId, bool sendRemoteUpdat
       if (auto version = clientInfo->clientSlavesNetVersion.ptr(entityId)) {
         if (auto updateSetPacket = updateSetPackets.value(connectionId)) {
           auto pair = make_pair(entityId, *version);
-          auto& cache = netRules.isLegacy ? m_legacyNetStateCache : m_netStateCache;
+          auto& cache = m_netStateCache[netRules];
           auto i = cache.find(pair);
           if (i == cache.end())
             i = cache.insert(pair, monitoredEntity->writeNetState(*version, netRules)).first;
diff --git a/source/game/StarWorldServer.hpp b/source/game/StarWorldServer.hpp
index a87f72d..ea650ac 100644
--- a/source/game/StarWorldServer.hpp
+++ b/source/game/StarWorldServer.hpp
@@ -374,8 +374,7 @@ private:
   CollisionGenerator m_collisionGenerator;
   List<CollisionBlock> m_workingCollisionBlocks;
 
-  HashMap<pair<EntityId, uint64_t>, pair<ByteArray, uint64_t>> m_netStateCache;
-  HashMap<pair<EntityId, uint64_t>, pair<ByteArray, uint64_t>> m_legacyNetStateCache;
+  HashMap<NetCompatibilityRules, HashMap<pair<EntityId, uint64_t>, pair<ByteArray, uint64_t>>> m_netStateCache;
   OrderedHashMap<ConnectionId, shared_ptr<ClientInfo>> m_clientInfo;
 
   GameTimer m_entityUpdateTimer;