diff --git a/doc/examples/icatexport.py b/doc/examples/icatexport.py
index 07f7d465..43b50d35 100755
--- a/doc/examples/icatexport.py
+++ b/doc/examples/icatexport.py
@@ -44,7 +44,7 @@
                     default='USER')
 client, conf = config.getconfig()
 
-if client.apiversion < '4.4':
+if client.apiversion < '4.4.0':
     raise RuntimeError("Sorry, ICAT version %s is too old, need 4.4.0 or newer."
                        % client.apiversion)
 client.login(conf.auth, conf.credentials)
diff --git a/doc/examples/icatimport.py b/doc/examples/icatimport.py
index bd940668..74a45cbc 100755
--- a/doc/examples/icatimport.py
+++ b/doc/examples/icatimport.py
@@ -44,7 +44,7 @@
                     default='USER')
 client, conf = config.getconfig()
 
-if client.apiversion < '4.4':
+if client.apiversion < '4.4.0':
     raise RuntimeError("Sorry, ICAT version %s is too old, need 4.4.0 or newer."
                        % client.apiversion)
 client.login(conf.auth, conf.credentials)
diff --git a/icat/client.py b/icat/client.py
index 4635e395..9d713756 100644
--- a/icat/client.py
+++ b/icat/client.py
@@ -146,7 +146,7 @@ def __init__(self, url, idsurl=None,
         self.apiversion = Version(apiversion)
         log.debug("Connect to %s, ICAT version %s", url, self.apiversion)
 
-        if self.apiversion < '4.3':
+        if self.apiversion < '4.3.0':
             warn(ClientVersionWarning(self.apiversion, "too old"))
         self.entityInfoCache = {}
         self.typemap = getTypeMap(self)
@@ -370,7 +370,7 @@ def getAuthenticatorInfo(self):
         except suds.WebFault as e:
             raise translateError(e)
         except suds.MethodNotFound as e:
-            if self.apiversion < '4.9':
+            if self.apiversion < '4.9.0':
                 raise VersionMethodError("getAuthenticatorInfo", 
                                          self.apiversion)
             else:
diff --git a/icat/ids.py b/icat/ids.py
index 9185fdcf..6f9ac452 100644
--- a/icat/ids.py
+++ b/icat/ids.py
@@ -271,7 +271,7 @@ def getIcatUrl(self):
         try:
             return self.opener.open(req).read().decode('ascii')
         except (HTTPError, IDSError) as e:
-            raise self._versionMethodError("getIcatUrl", '1.4', e)
+            raise self._versionMethodError("getIcatUrl", '1.4.0', e)
 
     def isReadOnly(self):
         """See if the server is configured to be readonly.
@@ -344,7 +344,7 @@ def write(self, selection):
         try:
             self.opener.open(req)
         except (HTTPError, IDSError) as e:
-            raise self._versionMethodError("write", '1.9', e)
+            raise self._versionMethodError("write", '1.9.0', e)
 
     def reset(self, selection):
         """Reset data so that they can be queried again.
@@ -354,7 +354,7 @@ def reset(self, selection):
         try:
             self.opener.open(req)
         except (HTTPError, IDSError) as e:
-            raise self._versionMethodError("reset", '1.6', e)
+            raise self._versionMethodError("reset", '1.6.0', e)
 
     def prepareData(self, selection, compressFlag=False, zipFlag=False):
         """Prepare data for a subsequent :meth:`~icat.ids.IDSClient.getData`
@@ -388,7 +388,7 @@ def getDatafileIds(self, selection):
             result = self.opener.open(req).read().decode('ascii')
             return json.loads(result)['ids']
         except (HTTPError, IDSError) as e:
-            raise self._versionMethodError("getDatafileIds", '1.5', e)
+            raise self._versionMethodError("getDatafileIds", '1.5.0', e)
 
     def getData(self, selection, 
                 compressFlag=False, zipFlag=False, outname=None, offset=0):
diff --git a/icatdump.py b/icatdump.py
index c6b28454..8ddd8b20 100755
--- a/icatdump.py
+++ b/icatdump.py
@@ -34,7 +34,7 @@
                     default='YAML')
 client, conf = config.getconfig()
 
-if client.apiversion < '4.3':
+if client.apiversion < '4.3.0':
     raise RuntimeError("Sorry, ICAT version %s is too old, need 4.3.0 or newer."
                        % client.apiversion)
 client.login(conf.auth, conf.credentials)
diff --git a/icatingest.py b/icatingest.py
index 4c8cfe7b..6bd25116 100755
--- a/icatingest.py
+++ b/icatingest.py
@@ -51,7 +51,7 @@
                                "but required for uploadDatafiles.")
     conf.dataDir = os.path.abspath(conf.dataDir)
 
-if client.apiversion < '4.3':
+if client.apiversion < '4.3.0':
     raise RuntimeError("Sorry, ICAT version %s is too old, need 4.3.0 or newer."
                        % client.apiversion)
 client.login(conf.auth, conf.credentials)
diff --git a/tests/test_03_getversion.py b/tests/test_03_getversion.py
index c113db5e..ca3eabfe 100644
--- a/tests/test_03_getversion.py
+++ b/tests/test_03_getversion.py
@@ -19,7 +19,7 @@ def test_get_icat_version():
     # python-icat supports ICAT server 4.3 or newer.  But actually, we
     # just want to check that client.apiversion is set and supports
     # comparison with version strings.
-    assert client.apiversion > '1.0'
+    assert client.apiversion > '1.0.0'
     print("\nConnect to %s\nICAT version %s\n" % (conf.url, client.apiversion))
 
 
diff --git a/wipeicat.py b/wipeicat.py
index 5c47e8df..b0af6d19 100755
--- a/wipeicat.py
+++ b/wipeicat.py
@@ -18,7 +18,7 @@
 config = icat.config.Config(ids="optional")
 client, conf = config.getconfig()
 
-if client.apiversion < '4.3':
+if client.apiversion < '4.3.0':
     raise RuntimeError("Sorry, icat.server version %s is too old, "
                        "need 4.3.0 or newer." % client.apiversion)
 if client.ids and client.ids.apiversion < '1.6.0':