diff --git a/CHANGELOG b/CHANGELOG
index d22b2ded8f..0648366984 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,15 @@
 v1.5.0 (XXXX-XX-XX)
 -------------------
 
+* issue #751: Create database through API should return HTTP status code 201
+
+  By default, the server now returns HTTP 201 (created) when creating a new
+  database successfully. To keep compatibility with older ArangoDB versions, the
+  startup parameter `--server.default-api-compatibility` can be set to a value
+  of `10400` to indicate API compatibility with ArangoDB 1.4. The compatibility
+  can also be enforced by setting the `X-Arango-Version` HTTP header in a 
+  client request to this API on a per-request basis.
+
 * issue #748: add vertex filtering to AQL's TRAVERSAL[_TREE]() function
 
 * allow direct access from the `db` object to collections whose names start 
@@ -114,6 +123,9 @@ v1.5.0 (XXXX-XX-XX)
   result of <collection>.getIndexes() for each index. This is
   currently only implemented for hash indices and skiplist indices.
 
+v1.4.8 (xxxx-xx-xx)
+-------------------
+
 
 v1.4.7 (2014-01-23)
 -------------------
diff --git a/UnitTests/HttpInterface/api-database-spec.rb b/UnitTests/HttpInterface/api-database-spec.rb
index aa6332b292..d667d6590e 100644
--- a/UnitTests/HttpInterface/api-database-spec.rb
+++ b/UnitTests/HttpInterface/api-database-spec.rb
@@ -66,12 +66,34 @@ describe ArangoDB do
     after do
       ArangoDB.delete(api + "/#{name}")
     end
+    
+    it "creates a new database, old return code" do
+      body = "{\"name\" : \"#{name}\" }"
+      doc = ArangoDB.log_post("#{prefix}-create", api, :body => body, :headers => { "X-Arango-Version" => "1.4" })
+     
+      doc.code.should eq(200)
+      doc.headers['content-type'].should eq("application/json; charset=utf-8")
+      response = doc.parsed_response
+      response["result"].should eq(true)
+      response["error"].should eq(false)
+    end
+    
+    it "creates a new database, new return code" do
+      body = "{\"name\" : \"#{name}\" }"
+      doc = ArangoDB.log_post("#{prefix}-create", api, :body => body, :headers => { "X-Arango-Version" => "1.5" })
+     
+      doc.code.should eq(201)
+      doc.headers['content-type'].should eq("application/json; charset=utf-8")
+      response = doc.parsed_response
+      response["result"].should eq(true)
+      response["error"].should eq(false)
+    end
 
     it "creates a new database" do
       body = "{\"name\" : \"#{name}\" }"
       doc = ArangoDB.log_post("#{prefix}-create", api, :body => body)
      
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       response = doc.parsed_response
       response["result"].should eq(true)
@@ -115,7 +137,7 @@ describe ArangoDB do
       body = "{\"name\" : \"#{name}\" }"
       doc = ArangoDB.log_post("#{prefix}-re-create", api, :body => body)
      
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       
       doc = ArangoDB.log_post("#{prefix}-post", api, :body => body)
@@ -132,7 +154,7 @@ describe ArangoDB do
       body = "{\"name\" : \"#{name}\" }"
       doc = ArangoDB.log_post("#{prefix}-drop", api, :body => body)
 
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       
       doc = ArangoDB.log_delete("#{prefix}-drop", cmd)
@@ -158,7 +180,7 @@ describe ArangoDB do
       body = "{\"name\" : \"#{name}\" }"
       doc = ArangoDB.log_post("#{prefix}-create-properties", api, :body => body)
      
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       response = doc.parsed_response
       response["result"].should eq(true)
@@ -206,7 +228,7 @@ describe ArangoDB do
       body = "{\"name\" : \"#{name}\", \"users\": [ { \"username\": \"admin\", \"password\": \"secret\", \"extra\": { \"gender\": \"m\" } }, { \"username\": \"foxx\", \"active\": false } ] }"
       doc = ArangoDB.log_post("#{prefix}-create-users", api, :body => body)
      
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       response = doc.parsed_response
       response["result"].should eq(true)
@@ -268,7 +290,7 @@ describe ArangoDB do
       body = "{\"name\" : \"#{name}\", \"users\": [ { \"username\": \"\" } ] }"
       doc = ArangoDB.log_post("#{prefix}-create-users-invalid", api, :body => body)
      
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       response = doc.parsed_response
       response["result"].should eq(true)
@@ -305,7 +327,7 @@ describe ArangoDB do
       body = "{\"name\" : \"#{name}\" }"
       doc = ArangoDB.log_post("#{prefix}-check-system", api, :body => body)
      
-      doc.code.should eq(200)
+      doc.code.should eq(201)
       doc.headers['content-type'].should eq("application/json; charset=utf-8")
       response = doc.parsed_response
       response["result"].should eq(true)
diff --git a/UnitTests/HttpInterface/api-graph-spec.rb b/UnitTests/HttpInterface/api-graph-spec.rb
index e4700a080f..4adf271eb4 100644
--- a/UnitTests/HttpInterface/api-graph-spec.rb
+++ b/UnitTests/HttpInterface/api-graph-spec.rb
@@ -1424,6 +1424,27 @@ describe ArangoDB do
         doc.parsed_response['result'].count.should eq(4)
       end
 
+      it "checks list of vertices of a vertex with HAS and HAS_NOT compare" do
+
+        cmd = "/_api/graph/#{graph_name}/vertices"
+        body = "{\"batchSize\" : 100, \"filter\" : { \"properties\" : [ { \"key\" : \"optional1\", \"compare\" : \"HAS\" } ] } }"
+        doc = ArangoDB.log_post("#{prefix}", cmd, :body => body)
+        doc.code.should eq(201)
+        doc.parsed_response['error'].should eq(false)
+        doc.parsed_response['code'].should eq(201)
+        doc.parsed_response['result'].count.should eq(4)
+
+
+        cmd = "/_api/graph/#{graph_name}/vertices"
+        body = "{\"batchSize\" : 100, \"filter\" : { \"properties\" : [ { \"key\" : \"optional1\", \"compare\" : \"HAS_NOT\" } ] } }"
+        doc = ArangoDB.log_post("#{prefix}", cmd, :body => body)
+        doc.code.should eq(201)
+        doc.parsed_response['error'].should eq(false)
+        doc.parsed_response['code'].should eq(201)
+        doc.parsed_response['result'].count.should eq(1)
+
+      end
+
     end
 
 ################################################################################
diff --git a/js/actions/api-database.js b/js/actions/api-database.js
index 59c722f185..ec75ea390c 100644
--- a/js/actions/api-database.js
+++ b/js/actions/api-database.js
@@ -240,7 +240,7 @@ function get_api_database (req, res) {
 ///
 /// @RESTRETURNCODES
 /// 
-/// @RESTRETURNCODE{200}
+/// @RESTRETURNCODE{201}
 /// is returned if the database was created successfully.
 ///
 /// @RESTRETURNCODE{400}
@@ -272,7 +272,7 @@ function get_api_database (req, res) {
 ///     var response = logCurlRequest('POST', url, JSON.stringify(data));
 ///
 ///     db._dropDatabase(name);
-///     assert(response.code === 200);
+///     assert(response.code === 201);
 /// 
 ///     logJsonResponse(response);
 /// @END_EXAMPLE_ARANGOSH_RUN
@@ -306,7 +306,7 @@ function get_api_database (req, res) {
 ///     var response = logCurlRequest('POST', url, JSON.stringify(data));
 ///
 ///     db._dropDatabase(name);
-///     assert(response.code === 200);
+///     assert(response.code === 201);
 /// 
 ///     logJsonResponse(response);
 /// @END_EXAMPLE_ARANGOSH_RUN
@@ -374,7 +374,8 @@ function post_api_database (req, res) {
 
   var result = arangodb.db._createDatabase(json.name || "", options, users);
 
-  actions.resultOk(req, res, actions.HTTP_OK, { result : result });
+  var returnCode = (req.compatibility <= 10400 ? actions.HTTP_OK : actions.HTTP_CREATED);
+  actions.resultOk(req, res, returnCode, { result : result });
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/js/actions/api-endpoint.js b/js/actions/api-endpoint.js
index 3e774b4625..b999d3648e 100644
--- a/js/actions/api-endpoint.js
+++ b/js/actions/api-endpoint.js
@@ -30,9 +30,6 @@
 
 var arangodb = require("org/arangodb");
 var actions = require("org/arangodb/actions");
-
-var db = arangodb.db;
-
 var internal = require("internal");
 
 // -----------------------------------------------------------------------------
diff --git a/js/actions/api-explain.js b/js/actions/api-explain.js
index 16368629d2..b6432ec153 100644
--- a/js/actions/api-explain.js
+++ b/js/actions/api-explain.js
@@ -30,7 +30,6 @@
 
 var actions = require("org/arangodb/actions");
 
-var ArangoError = require("org/arangodb").ArangoError; 
 var ERRORS = require("internal").errors;
 var EXPLAIN = require("internal").AQL_EXPLAIN;
 
diff --git a/js/actions/api-graph.js b/js/actions/api-graph.js
index 8e768af373..15a15473c6 100644
--- a/js/actions/api-graph.js
+++ b/js/actions/api-graph.js
@@ -1046,6 +1046,18 @@ function process_property_compare (compare) {
 ////////////////////////////////////////////////////////////////////////////////
 
 function process_property_filter (data, num, property, collname) {
+  if (property.key !== undefined && property.compare === "HAS") {
+      if (data.filter === "") { data.filter = " FILTER"; } else { data.filter += " &&";}
+      data.filter += " HAS(" + collname + ", @key" + num.toString() + ") ";
+      data.bindVars["key" + num.toString()] = property.key;
+      return;    
+  }
+  if (property.key !== undefined && property.compare === "HAS_NOT") {
+      if (data.filter === "") { data.filter = " FILTER"; } else { data.filter += " &&";}
+      data.filter += " !HAS(" + collname + ", @key" + num.toString() + ") ";
+      data.bindVars["key" + num.toString()] = property.key;
+      return;    
+  }
   if (property.key !== undefined && property.value !== undefined) {
       if (data.filter === "") { data.filter = " FILTER"; } else { data.filter += " &&";}
       data.filter += " " + collname + "[@key" + num.toString() + "] " +
diff --git a/js/actions/api-simple.js b/js/actions/api-simple.js
index 72eec5ba18..fb20a633c0 100644
--- a/js/actions/api-simple.js
+++ b/js/actions/api-simple.js
@@ -29,7 +29,6 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 var actions = require("org/arangodb/actions");
-var simple = require("org/arangodb/simple-query");
 var db = require("org/arangodb").db;
 var ERRORS = require("internal").errors;
 
diff --git a/js/actions/api-structure.js b/js/actions/api-structure.js
index fb5c95110b..2efe566eab 100644
--- a/js/actions/api-structure.js
+++ b/js/actions/api-structure.js
@@ -40,7 +40,6 @@ var console = require("console");
 var actions = require("org/arangodb/actions");
 var arangodb = require("org/arangodb");
 var db = arangodb.db;
-var ERRORS = arangodb.errors;
 
 var DEFAULT_KEY = "default";
 var API = "_api/structure";
diff --git a/js/actions/api-system.js b/js/actions/api-system.js
index b4bad15406..ecab39568a 100644
--- a/js/actions/api-system.js
+++ b/js/actions/api-system.js
@@ -30,9 +30,6 @@
 
 var arangodb = require("org/arangodb");
 var actions = require("org/arangodb/actions");
-
-var db = arangodb.db;
-
 var internal = require("internal");
 var console = require("console");
 
diff --git a/js/actions/api-user.js b/js/actions/api-user.js
index 31d01886c1..743cdaae42 100644
--- a/js/actions/api-user.js
+++ b/js/actions/api-user.js
@@ -32,8 +32,6 @@ var arangodb = require("org/arangodb");
 var actions = require("org/arangodb/actions");
 var users = require("org/arangodb/users");
 
-var ArangoError = arangodb.ArangoError; 
-
 // -----------------------------------------------------------------------------
 // --SECTION--                                                 private functions
 // -----------------------------------------------------------------------------
@@ -163,7 +161,7 @@ function post_api_user (req, res) {
     return;
   }
 
-  var result = users.save(json.username, json.passwd, json.active, json.extra);
+  users.save(json.username, json.passwd, json.active, json.extra);
   users.reload();
 
   actions.resultOk(req, res, actions.HTTP_CREATED, { });
@@ -251,7 +249,7 @@ function put_api_user (req, res) {
   }
   
   try {
-    var result = users.replace(username, json.passwd, json.active, json.extra);
+    users.replace(username, json.passwd, json.active, json.extra);
     users.reload();
   
     actions.resultOk(req, res, actions.HTTP_OK, { });
@@ -350,7 +348,7 @@ function patch_api_user (req, res) {
   }
   
   try {
-    var result = users.update(username, json.passwd, json.active, json.extra);
+    users.update(username, json.passwd, json.active, json.extra);
     users.reload();
     actions.resultOk(req, res, actions.HTTP_OK, { });
   }
@@ -419,7 +417,7 @@ function delete_api_user (req, res) {
 
   var username = decodeURIComponent(req.suffix[0]);
   try {
-    var result = users.remove(username);
+    users.remove(username);
     users.reload();
     actions.resultOk(req, res, actions.HTTP_ACCEPTED, { });
   }
diff --git a/js/actions/key-value.js b/js/actions/key-value.js
index 57cd0b3020..e6258c797f 100644
--- a/js/actions/key-value.js
+++ b/js/actions/key-value.js
@@ -39,7 +39,6 @@
 // -----------------------------------------------------------------------------
 
 var actions = require("org/arangodb/actions");
-var simple = require("org/arangodb/simple-query");
 var db = require("org/arangodb").db;
 var internal = require("internal");
 var arangodb = require("org/arangodb");
diff --git a/js/apps/system/aardvark/frontend/js/views/dbSelectionView.js b/js/apps/system/aardvark/frontend/js/views/dbSelectionView.js
index df9debf6ac..5ff1505ece 100644
--- a/js/apps/system/aardvark/frontend/js/views/dbSelectionView.js
+++ b/js/apps/system/aardvark/frontend/js/views/dbSelectionView.js
@@ -11,7 +11,6 @@
     },
 
     initialize: function(opts) {
-      var self = this;
       this.current = opts.current;
       this.collection.fetch({
         async: false
diff --git a/js/apps/system/aardvark/frontend/js/views/footerView.js b/js/apps/system/aardvark/frontend/js/views/footerView.js
index 194d4c3c97..973c910fcd 100644
--- a/js/apps/system/aardvark/frontend/js/views/footerView.js
+++ b/js/apps/system/aardvark/frontend/js/views/footerView.js
@@ -94,7 +94,6 @@
     },
 
     renderVersion: function () {
-      var self = this;
       if (this.system.hasOwnProperty('database') && this.system.hasOwnProperty('name')) {
         $(this.el).html(this.template.render({
           name: this.system.name,
@@ -116,7 +115,6 @@
     },
 
     render: function () {
-      var self = this;
       if (!this.system.version) {
         this.getVersion();
       }
diff --git a/js/apps/system/aardvark/lib/swagger.js b/js/apps/system/aardvark/lib/swagger.js
index 5aba5fd84e..a75f5fe843 100644
--- a/js/apps/system/aardvark/lib/swagger.js
+++ b/js/apps/system/aardvark/lib/swagger.js
@@ -31,9 +31,7 @@
 exports.Swagger = function () {
   "use strict";
   
-  // Define the Repository
-  var Foxx = require("org/arangodb/foxx"),
-    db = require("internal").db,
+  var db = require("internal").db,
     _routing = db._collection("_routing"),
     _aal = db._collection("_aal"),
     _ = require("underscore"),
diff --git a/lib/ProgramOptions/program-options.c b/lib/ProgramOptions/program-options.c
index 8bdfa465e9..15271f208b 100644
--- a/lib/ProgramOptions/program-options.c
+++ b/lib/ProgramOptions/program-options.c
@@ -187,18 +187,21 @@ static char * FillVariables (const char* value) {
           if (v == NULL) {
             if (TRI_EqualString(k, "ROOTDIR")) {
               char* vv = TRI_LocateInstallDirectory();
-              size_t lv = strlen(vv);
 
-              if (0 < lv) {
-                if (vv[lv - 1] == TRI_DIR_SEPARATOR_CHAR || vv[lv - 1] == '/') {
-                  v = TRI_DuplicateString2(vv, lv - 1);
-                }
-                else {
-                  v = TRI_DuplicateString2(vv, lv);
+              if (vv != NULL) {
+                size_t lv = strlen(vv);
+
+                if (0 < lv) {
+                  if (vv[lv - 1] == TRI_DIR_SEPARATOR_CHAR || vv[lv - 1] == '/') {
+                    v = TRI_DuplicateString2(vv, lv - 1);
+                  }
+                  else {
+                    v = TRI_DuplicateString2(vv, lv);
+                  }
                 }
+
+                TRI_FreeString(TRI_CORE_MEM_ZONE, vv);
               }
-
-              TRI_FreeString(TRI_CORE_MEM_ZONE, vv);
             }
           }
           else {