diff --git a/onionr/api.py b/onionr/api.py
index 146d43c5..94c7eeaa 100755
--- a/onionr/api.py
+++ b/onionr/api.py
@@ -22,7 +22,7 @@ from flask import request, Response, abort, send_from_directory
 from multiprocessing import Process
 from gevent.pywsgi import WSGIServer
 import sys, random, threading, hmac, hashlib, base64, time, math, os, json
-from core import Core
+import core
 from onionrblockapi import Block
 import onionrutils, onionrexceptions, onionrcrypto, blockimporter, onionrevents as events, logger, config
 
@@ -69,7 +69,7 @@ class API:
         logger.debug('%s not in %s' % (path, mimetypes))
         return 'text/plain'
 
-    def __init__(self, debug):
+    def __init__(self, debug, API_VERSION):
         '''
             Initialize the api server, preping variables for later use
 
@@ -88,7 +88,7 @@ class API:
 
         self.debug = debug
         self._privateDelayTime = 3
-        self._core = Core()
+        self._core = core.Core()
         self._crypto = onionrcrypto.OnionrCrypto(self._core)
         self._utils = onionrutils.OnionrUtils(self._core)
         app = flask.Flask(__name__)
@@ -133,7 +133,7 @@ class API:
                 resp.headers["Content-Security-Policy"] =  "default-src 'none'; script-src 'none'; object-src 'none'; style-src data: 'unsafe-inline'; img-src data:; media-src 'none'; frame-src 'none'; font-src 'none'; connect-src 'none'"
             resp.headers['X-Frame-Options'] = 'deny'
             resp.headers['X-Content-Type-Options'] = "nosniff"
-            resp.headers['server'] = 'Onionr'
+            resp.headers['api'] = API_VERSION
 
             # reset to text/plain to help prevent browser attacks
             self.mimeType = 'text/plain'
diff --git a/onionr/onionr.py b/onionr/onionr.py
index 80737bde..eb56fb7c 100755
--- a/onionr/onionr.py
+++ b/onionr/onionr.py
@@ -30,7 +30,6 @@ import webbrowser
 from threading import Thread
 import api, core, config, logger, onionrplugins as plugins, onionrevents as events
 import onionrutils
-from onionrutils import OnionrUtils
 from netcontroller import NetController
 from onionrblockapi import Block
 import onionrproofs, onionrexceptions, onionrusers
@@ -98,7 +97,7 @@ class Onionr:
             logger.set_level(logger.LEVEL_INFO)
 
         self.onionrCore = core.Core()
-        self.onionrUtils = OnionrUtils(self.onionrCore)
+        self.onionrUtils = onionrutils.OnionrUtils(self.onionrCore)
 
         # Handle commands
 
@@ -636,7 +635,7 @@ class Onionr:
         '''
         communicatorDaemon = './communicator2.py'
 
-        apiThread = Thread(target=api.API, args=(self.debug,))
+        apiThread = Thread(target=api.API, args=(self.debug,API_VERSION))
         apiThread.start()
         try:
             time.sleep(3)
diff --git a/onionr/onionrexceptions.py b/onionr/onionrexceptions.py
index f3cefe36..d450e3ae 100644
--- a/onionr/onionrexceptions.py
+++ b/onionr/onionrexceptions.py
@@ -65,6 +65,9 @@ class MissingPort(Exception):
 class InvalidAddress(Exception):
     pass
 
+class InvalidAPIVersion(Exception):
+    pass
+
 # file exceptions
 
 class DiskAllocationReached(Exception):
diff --git a/onionr/onionrutils.py b/onionr/onionrutils.py
index a17d27bc..5cc79e90 100644
--- a/onionr/onionrutils.py
+++ b/onionr/onionrutils.py
@@ -22,6 +22,7 @@ import getpass, sys, requests, os, socket, hashlib, logger, sqlite3, config, bin
 import nacl.signing, nacl.encoding
 from onionrblockapi import Block
 import onionrexceptions
+from onionr import API_VERSION
 from defusedxml import minidom
 import onionrevents
 import pgpwords, onionrusers, storagecounter
@@ -614,11 +615,16 @@ class OnionrUtils:
         try:
             proxies = {'http': 'socks4a://127.0.0.1:' + str(port), 'https': 'socks4a://127.0.0.1:' + str(port)}
             r = requests.get(url, headers=headers, proxies=proxies, allow_redirects=False, timeout=(15, 30))
+            # Check server is using same API version as us
+            if r.headers['api'] != str(API_VERSION):
+                raise onionrexceptions.InvalidAPIVersion
             retData = r.text
         except KeyboardInterrupt:
             raise KeyboardInterrupt
         except ValueError as e:
             logger.debug('Failed to make request', error = e)
+        except onionrexceptions.InvalidAPIVersion:
+            logger.debug("Node is using different API version :(")
         except requests.exceptions.RequestException as e:
             if not 'ConnectTimeoutError' in str(e) and not 'Request rejected or failed' in str(e):
                 logger.debug('Error: %s' % str(e))