diff --git a/lib/core/agent.py b/lib/core/agent.py
index 488ba7a8c..46a332da4 100644
--- a/lib/core/agent.py
+++ b/lib/core/agent.py
@@ -51,6 +51,7 @@ from lib.core.settings import REPLACEMENT_MARKER
 from lib.core.settings import SINGLE_QUOTE_MARKER
 from lib.core.settings import SLEEP_TIME_MARKER
 from lib.core.unescaper import unescaper
+from thirdparty import six
 
 class Agent(object):
     """
@@ -308,7 +309,7 @@ class Agent(object):
         return re.sub(r";\W*;", ";", expression) if trimEmpty else expression
 
     def cleanupPayload(self, payload, origValue=None):
-        if payload is None:
+        if not isinstance(payload, six.string_types):
             return
 
         replacements = {
diff --git a/lib/core/settings.py b/lib/core/settings.py
index 8de238665..95a4bc050 100644
--- a/lib/core/settings.py
+++ b/lib/core/settings.py
@@ -18,7 +18,7 @@ from lib.core.enums import OS
 from thirdparty.six import unichr as _unichr
 
 # sqlmap version (<major>.<minor>.<month>.<monthly commit>)
-VERSION = "1.3.8.18"
+VERSION = "1.3.8.19"
 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)