diff --git a/src/trinityrealm/AuthCodes.h b/src/trinityrealm/AuthCodes.h
index 53ae2236bc..e0bfcf96ce 100644
--- a/src/trinityrealm/AuthCodes.h
+++ b/src/trinityrealm/AuthCodes.h
@@ -72,8 +72,19 @@ enum LoginResult
 //2.4.3 build 8606
 //3.1.3 build 9947
 //3.1.3 build 10146 Chinese build
-//3.2.2a build 10505
 
-#define EXPECTED_TRINITY_CLIENT_BUILD        {10505, 10146, 9947, 8606, 5875, 6005, 0}
+#define POST_BC_ACCEPTED_CLIENT_BUILD                 {10505, 10146, 9947, 8606, 0}
+#define PRE_BC_ACCEPTED_CLIENT_BUILD                  {5875, 6005, 0}
+
+#define POST_BC_EXP_FLAG                              0x2
+#define PRE_BC_EXP_FLAG                               0x1
+#define NO_VALID_EXP_FLAG                             0x0
+
+namespace AuthHelper
+{
+    bool IsAcceptedClientBuild(int build);
+    bool IsPostBCAcceptedClientBuild(int build);
+    bool IsPreBCAcceptedClientBuild(int build);
+};
 
 #endif
diff --git a/src/trinityrealm/AuthSocket.cpp b/src/trinityrealm/AuthSocket.cpp
index bd79fc5d20..a19d16106f 100644
--- a/src/trinityrealm/AuthSocket.cpp
+++ b/src/trinityrealm/AuthSocket.cpp
@@ -379,6 +379,7 @@ bool AuthSocket::_HandleLogonChallenge()
 
     _login = (const char*)ch->I;
     _build = ch->build;
+    _expversion = (AuthHelper::IsPostBCAcceptedClientBuild(_build) ? POST_BC_EXP_FLAG : NO_VALID_EXP_FLAG) + (AuthHelper::IsPreBCAcceptedClientBuild(_build) ? PRE_BC_EXP_FLAG : NO_VALID_EXP_FLAG);
 
     ///- Normalize account name
     //utf8ToUpperOnlyLatin(_login); -- client already send account in expected form
@@ -549,22 +550,10 @@ bool AuthSocket::_HandleLogonProof()
     sAuthLogonProof_C lp;
     ibuf.Read((char *)&lp, sizeof(sAuthLogonProof_C));
 
-    ///- Check if the client has one of the expected version numbers
-    bool valid_version = false;
-    int accepted_versions[] = EXPECTED_TRINITY_CLIENT_BUILD;
-    for (int i = 0; accepted_versions[i]; ++i)
-    {
-        if (_build == accepted_versions[i])
-        {
-            valid_version = true;
-            break;
-        }
-    }
-
     /// <ul><li> If the client has no valid version
-    if (!valid_version)
+    if (_expversion == NO_VALID_EXP_FLAG)
     {
-        ///- Check if we have the apropriate patch on the disk
+        ///- Check if we have the appropriate patch on the disk
 
         // 24 = len("./patches/65535enGB.mpq")+1
         char tmp[24];
@@ -706,7 +695,7 @@ bool AuthSocket::_HandleLogonProof()
         sha.UpdateBigNumbers(&A, &M, &K, NULL);
         sha.Finalize();
 
-        if (_build == 8606 || _build == 9947 || _build == 10146 || _build == 10505)//2.4.3, 3.1.3 and 3.2.2a clients (10146 is Chinese build for 3.1.3)
+        if (_expversion & POST_BC_EXP_FLAG)//2.4.3 and 3.1.3 clients (10146 is Chinese build for 3.1.3)
         {
             sAuthLogonProof_S proof;
             memcpy(proof.M2, sha.GetDigest(), 20);
@@ -909,14 +898,14 @@ bool AuthSocket::_HandleRealmList()
     RealmList built_realmList;
     for (rlm = m_realmList.begin(); rlm != m_realmList.end(); ++rlm)
     {
-        if (_build == 8606 || _build == 9947 || _build == 10146 || _build == 10505)//2.4.3, 3.1.3 and 3.2.2a clients
+        if ( _expversion & POST_BC_EXP_FLAG )//2.4.3 and 3.1.3 cliens
         {
             if (rlm->second.gamebuild == _build)
                 built_realmList.AddRealm(rlm->second);
         }
-        else if (_build == 5875 || _build == 6005)//1.12.1 and 1.12.2 clients are compatible with eachother
+        else if ( _expversion & PRE_BC_EXP_FLAG )//1.12.1 and 1.12.2 clients are compatible with eachother
         {
-            if (rlm->second.gamebuild == 5875 || rlm->second.gamebuild == 6005)
+            if ( AuthHelper::IsPreBCAcceptedClientBuild ( rlm->second.gamebuild ) )
                 built_realmList.AddRealm(rlm->second);
         }
 
@@ -925,7 +914,7 @@ bool AuthSocket::_HandleRealmList()
     ///- Circle through realms in the RealmList and construct the return packet (including # of user characters in each realm)
     ByteBuffer pkt;
     pkt << (uint32) 0;
-    if (_build == 8606 || _build == 9947 || _build == 10146 || _build == 10505)//only 2.4.3, 3.1.3 and 3.2.2a clients
+    if (  _expversion & POST_BC_EXP_FLAG )//only 2.4.3 and 3.1.3 cliens
         pkt << (uint16) built_realmList.size();
     else
         pkt << (uint32) built_realmList.size();
@@ -948,7 +937,7 @@ bool AuthSocket::_HandleRealmList()
         uint8 lock = (i->second.allowedSecurityLevel > _accountSecurityLevel) ? 1 : 0;
 
         pkt << i->second.icon;                             // realm type
-        if (i->second.gamebuild == 10505 || i->second.gamebuild == 9947 || i->second.gamebuild == 10146 || i->second.gamebuild == 8606)//only 2.4.3, 3.1.3 and 3.2.2a clients
+        if ( _expversion & POST_BC_EXP_FLAG )//only 2.4.3 and 3.1.3 cliens
             pkt << lock;                                       // if 1, then realm locked
         pkt << i->second.color;                            // if 2, then realm is offline
         pkt << i->first;
@@ -956,13 +945,13 @@ bool AuthSocket::_HandleRealmList()
         pkt << i->second.populationLevel;
         pkt << AmountOfCharacters;
         pkt << i->second.timezone;                          // realm category
-        if (i->second.gamebuild == 10505 || i->second.gamebuild == 9947 || i->second.gamebuild == 10146 || i->second.gamebuild == 8606)//2.4.3, 3.1.3 and 3.2.2a clients
+        if ( _expversion & POST_BC_EXP_FLAG )//2.4.3 and 3.1.3 clients
             pkt << (uint8) 0x2C;                                // unk, may be realm number/id?
         else
             pkt << (uint8) 0x0; //1.12.1 and 1.12.2 clients
     }
 
-    if (_build == 10505 || _build == 9947 || _build == 10146 || _build == 8606)//2.4.3, 3.1.3 and 3.2.2a clients
+    if ( _expversion & POST_BC_EXP_FLAG )//2.4.3 and 3.1.3 cliens
     {
         pkt << (uint8) 0x10;
         pkt << (uint8) 0x00;
diff --git a/src/trinityrealm/AuthSocket.h b/src/trinityrealm/AuthSocket.h
index ecfdd15900..474ead8659 100644
--- a/src/trinityrealm/AuthSocket.h
+++ b/src/trinityrealm/AuthSocket.h
@@ -79,6 +79,7 @@ class AuthSocket: public TcpSocket
         // between enUS and enGB, which is important for the patch system
         std::string _localizationName;
         uint16 _build;
+        uint8 _expversion;
         AccountTypes _accountSecurityLevel;
 };
 #endif
diff --git a/src/trinityrealm/CMakeLists.txt b/src/trinityrealm/CMakeLists.txt
index 85c2120b5d..e39dc088e9 100644
--- a/src/trinityrealm/CMakeLists.txt
+++ b/src/trinityrealm/CMakeLists.txt
@@ -1,6 +1,7 @@
 ########### next target ###############
 
 SET(trinity-realm_SRCS
+AuthCodes.cpp
 AuthCodes.h
 AuthSocket.cpp
 AuthSocket.h