diff --git a/lib/core/settings.py b/lib/core/settings.py
index b751504d9..8d07f9ac8 100644
--- a/lib/core/settings.py
+++ b/lib/core/settings.py
@@ -20,7 +20,7 @@ from thirdparty import six
 from thirdparty.six import unichr as _unichr
 
 # sqlmap version (<major>.<minor>.<month>.<monthly commit>)
-VERSION = "1.6.2.3"
+VERSION = "1.6.2.4"
 TYPE = "dev" if VERSION.count('.') > 2 and VERSION.split('.')[-1] != '0' else "stable"
 TYPE_COLORS = {"dev": 33, "stable": 90, "pip": 34}
 VERSION_STRING = "sqlmap/%s#%s" % ('.'.join(VERSION.split('.')[:-1]) if VERSION.count('.') > 2 and VERSION.split('.')[-1] == '0' else VERSION, TYPE)
diff --git a/lib/request/connect.py b/lib/request/connect.py
index 7d2fafc16..73da27611 100644
--- a/lib/request/connect.py
+++ b/lib/request/connect.py
@@ -1430,7 +1430,7 @@ class Connect(object):
 
                 deviation = stdev(kb.responseTimes[kb.responseTimeMode])
 
-                if deviation > WARN_TIME_STDEV:
+                if deviation is not None and deviation > WARN_TIME_STDEV:
                     kb.adjustTimeDelay = ADJUST_TIME_DELAY.DISABLE
 
                     warnMsg = "considerable lagging has been detected "