diff --git a/lib/core/settings.py b/lib/core/settings.py
index 2e6d131eb..320bf7cc5 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 = "1.4.7.19"
+VERSION = "1.4.7.20"
 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/tamper/misunion.py b/tamper/misunion.py
new file mode 100644
index 000000000..bb8d3be09
--- /dev/null
+++ b/tamper/misunion.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+
+"""
+Copyright (c) 2006-2020 sqlmap developers (http://sqlmap.org/)
+See the file 'LICENSE' for copying permission
+"""
+
+import re
+
+from lib.core.enums import PRIORITY
+
+__priority__ = PRIORITY.HIGHEST
+
+def dependencies():
+    pass
+
+def tamper(payload, **kwargs):
+    """
+    Replaces instances of UNION with -.1UNION
+
+    Requirement:
+        * MySQL
+
+    Notes:
+        * Reference: https://raw.githubusercontent.com/y0unge/Notes/master/SQL%20Injection%20WAF%20Bypassing%20shortcut.pdf
+
+    >>> tamper('1 UNION ALL SELECT')
+    '1-.1UNION ALL SELECT'
+    >>> tamper('1" UNION ALL SELECT')
+    '1"-.1UNION ALL SELECT'
+    """
+
+    return re.sub("\s+(UNION )", r"-.1\g<1>", payload, re.I) if payload else payload