diff --git a/js/models/core/BuilderMockV0.js b/js/models/core/BuilderMockV0.js
deleted file mode 100644
index be3926d10..000000000
--- a/js/models/core/BuilderMockV0.js
+++ /dev/null
@@ -1,26 +0,0 @@
-'use strict';
-
-
-var bitcore = require('bitcore');
-var Transaction = bitcore.Transaction;
-
-function BuilderMockV0 (data) {
-  this.vanilla = data;
-  this.tx = new Transaction();
-  this.tx.parse(new Buffer(data.tx, 'hex'));
-};
-
-BuilderMockV0.prototype.build = function() {
-  return this.tx;
-}; 
-
-
-BuilderMockV0.prototype.getSelectedUnspent = function() {
-  return [];
-};
-
-BuilderMockV0.prototype.toObj = function() {
-  return this.vanilla;
-};
-
-module.exports = BuilderMockV0;
diff --git a/js/models/core/TxProposal.js b/js/models/core/TxProposal.js
index 2340bde8d..9f2aa78e2 100644
--- a/js/models/core/TxProposal.js
+++ b/js/models/core/TxProposal.js
@@ -4,7 +4,6 @@ var bitcore = require('bitcore');
 var _ = require('underscore');
 var util = bitcore.util;
 var Transaction = bitcore.Transaction;
-var BuilderMockV0 = require('./BuilderMockV0');;
 var TransactionBuilder = bitcore.TransactionBuilder;
 var Script = bitcore.Script;
 var Key = bitcore.Key;
@@ -134,12 +133,7 @@ TxProposal.fromObj = function(o, forceOpts) {
     }
     o.builder = TransactionBuilder.fromObj(o.builderObj);
   } catch (e) {
-
-    // backwards (V0) compatatibility fix.
-    if (!o.version) {
-      o.builder = new BuilderMockV0(o.builderObj);
-      o.readonly = 1;
-    };
+    throw new Error("Invalid or Incompatible Backup Detected.");
   }
   return new TxProposal(o);
 };
diff --git a/js/models/core/TxProposals.js b/js/models/core/TxProposals.js
index 9e33d6eab..f1021be14 100644
--- a/js/models/core/TxProposals.js
+++ b/js/models/core/TxProposals.js
@@ -1,11 +1,9 @@
 'use strict';
 
-var BuilderMockV0 = require('./BuilderMockV0');;
 var bitcore = require('bitcore');
 var util = bitcore.util;
 var Transaction = bitcore.Transaction;
-var BuilderMockV0 = require('./BuilderMockV0');;
-var TxProposal = require('./TxProposal');;
+var TxProposal = require('./TxProposal');
 var Script = bitcore.Script;
 var Key = bitcore.Key;
 var buffertools = bitcore.buffertools;
diff --git a/test/test.TxProposal.js b/test/test.TxProposal.js
index 9ad7fe2a8..3e22e130c 100644
--- a/test/test.TxProposal.js
+++ b/test/test.TxProposal.js
@@ -133,7 +133,7 @@ describe('TxProposal', function() {
           builderObj: b.toObj(),
           inputChainPaths: ['m/1'],
         });
-      }).should.throw('Invalid');
+      }).should.throw('Invalid or Incompatible Backup Detected');
     });
 
 
diff --git a/test/test.WalletFactory.js b/test/test.WalletFactory.js
index b79bdcd5c..058f91c9b 100644
--- a/test/test.WalletFactory.js
+++ b/test/test.WalletFactory.js
@@ -432,16 +432,13 @@ describe('WalletFactory model', function() {
       wf.network.start.getCall(0).args[0].privkey.length.should.equal(64); //privkey is hex of private key buffer
     });
   });
-  describe('dont break backwards compatibility of wallets', function() {
-    it('should be able to import unencrypted legacy wallet TxProposal: v0', function() {
-      var wf = new WalletFactory(config, '0.0.5');
-      var w = wf.fromObj(JSON.parse(legacyO));
+  describe('break backwards compatibility with older versions', function() {
+    it('should\'nt be able to import unencrypted legacy wallet TxProposal: v0', function() {
 
-      should.exist(w);
-      w.id.should.equal('55d4bd062d32f90a');
-      should.exist(w.publicKeyRing.getCopayerId);
-      should.exist(w.txProposals.toObj());
-      should.exist(w.privateKey.toObj());
+      (function() {
+        var wf = new WalletFactory(config, '0.0.5');
+        var w = wf.fromObj(JSON.parse(legacyO));
+      }).should.throw('Invalid or Incompatible Backup Detected');
     });
 
     it('should be able to import simple 1-of-1 encrypted legacy testnet wallet', function(done) {