--- a/src/db.cpp
+++ b/src/db.cpp
@@ -940,6 +940,7 @@
                 ssValue >> nMinVersion;
                 if (nMinVersion > CLIENT_VERSION)
                     return DB_TOO_NEW;
+                pwallet->LoadMinVersion(nMinVersion);
             }
             else if (strType == "cscript")
             {

--- a/src/db.h
+++ b/src/db.h
@@ -486,6 +486,11 @@
         return Write(std::make_pair(std::string("setting"), strKey), value);
     }
 
+    bool WriteMinVersion(int nVersion)
+    {
+        return Write(std::string("minversion"), nVersion);
+    }
+
     bool ReadAccount(const std::string& strAccount, CAccount& account);
     bool WriteAccount(const std::string& strAccount, const CAccount& account);
     bool WriteAccountingEntry(const CAccountingEntry& acentry);

--- a/src/wallet.cpp
+++ b/src/wallet.cpp
@@ -131,6 +131,32 @@
     )
 };
 
+bool CWallet::SetMinVersion(int nVersion, CWalletDB* pwalletdbIn)
+{
+    if (nWalletVersion >= nVersion)
+        return true;
+
+    nWalletVersion = nVersion;
+
+    if (fFileBacked)
+    {
+        CWalletDB* pwalletdb = pwalletdbIn ? pwalletdbIn : new CWalletDB(strWalletFile);
+        if (nWalletVersion >= 40000)
+        {
+            // Versions prior to 0.4.0 did not support the "minversion" record.
+            // Use a CCorruptAddress to make them crash instead.
+            CCorruptAddress corruptAddress;
+            pwalletdb->WriteSetting("addrIncoming", corruptAddress);
+        }
+        if (nWalletVersion > 40000)
+            pwalletdb->WriteMinVersion(nWalletVersion);
+        if (!pwalletdbIn)
+            delete pwalletdb;
+    }
+
+    return true;
+}
+
 bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
 {
     if (IsCrypted())
@@ -184,10 +210,11 @@
             exit(1); //We now probably have half of our keys encrypted in memory, and half not...die and let the user reload their unencrypted wallet.
         }
 
+        // Encryption was introduced in version 0.4.0
+        SetMinVersion(40000, pwalletdbEncryption);
+
         if (fFileBacked)
         {
-            CCorruptAddress corruptAddress;
-            pwalletdbEncryption->WriteSetting("addrIncoming", corruptAddress);
             if (!pwalletdbEncryption->TxnCommit())
                 exit(1); //We now have keys encrypted in memory, but no on disk...die to avoid confusion and let the user reload their unencrypted wallet.
 

--- a/src/wallet.h
+++ b/src/wallet.h
@@ -25,6 +25,8 @@
 
     CWalletDB *pwalletdbEncryption;
 
+    int nWalletVersion;
+
 public:
     mutable CCriticalSection cs_wallet;
 
@@ -33,18 +35,21 @@
 
     std::set<int64> setKeyPool;
 
+
     typedef std::map<unsigned int, CMasterKey> MasterKeyMap;
     MasterKeyMap mapMasterKeys;
     unsigned int nMasterKeyMaxID;
 
     CWallet()
     {
+        nWalletVersion = 0;
         fFileBacked = false;
         nMasterKeyMaxID = 0;
         pwalletdbEncryption = NULL;
     }
     CWallet(std::string strWalletFileIn)
     {
+        nWalletVersion = 0;
         strWalletFile = strWalletFileIn;
         fFileBacked = true;
         nMasterKeyMaxID = 0;
@@ -66,6 +71,8 @@
     // Adds a key to the store, without saving it to disk (used by LoadWallet)
     bool LoadKey(const CKey& key) { return CCryptoKeyStore::AddKey(key); }
 
+    bool LoadMinVersion(int nVersion) { nWalletVersion = nVersion; return true; }
+
     // Adds an encrypted key to the store, and saves it to disk.
     bool AddCryptedKey(const std::vector<unsigned char> &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
     // Adds an encrypted key to the store, without saving it to disk (used by LoadWallet)
@@ -206,6 +213,8 @@
     bool GetTransaction(const uint256 &hashTx, CWalletTx& wtx);
 
     bool SetDefaultKey(const std::vector<unsigned char> &vchPubKey);
+
+    bool SetMinVersion(int nVersion, CWalletDB* pwalletdbIn = NULL);
 };