diff --git a/data/txt/sha256sums.txt b/data/txt/sha256sums.txt
index a9782a330..3c23a99f8 100644
--- a/data/txt/sha256sums.txt
+++ b/data/txt/sha256sums.txt
@@ -173,7 +173,7 @@ a6397b10de7ae7c56ed6b0fa3b3c58eb7a9dbede61bf93d786e73258175c981e  lib/core/compa
 a9997e97ebe88e0bf7efcf21e878bc5f62c72348e5aba18f64d6861390a4dcf2  lib/core/convert.py
 c03dc585f89642cfd81b087ac2723e3e1bb3bfa8c60e6f5fe58ef3b0113ebfe6  lib/core/data.py
 e396b7971d38896e0e20b973a3a6a3fbc3171d080a21bc6e66a65bee452fd69c  lib/core/datatype.py
-35e99a327a357e22dcbcd5229a347102dfc58ff8105b420afdeffc8236a9ecf4  lib/core/decorators.py
+e18c0c2c5a57924a623792a48bfd36e98d9bc085f6db61a95fc0dc8a3bcedc0c  lib/core/decorators.py
 147823c37596bd6a56d677697781f34b8d1d1671d5a2518fbc9468d623c6d07d  lib/core/defaults.py
 86fa0ffa7a3e7a7141eab730e3981faf6f0249125ea9a29a57aaa8b65b7503f9  lib/core/dicts.py
 186f0331d66e861a942817a3321156a93a6f66c34a19ce90ec1d10aac8bc1cac  lib/core/dump.py
@@ -189,7 +189,7 @@ f5272cda54f7cdd07fb6154d5a1ed1f1141a2a4f39b6a85d3f325fd60ac8dc9a  lib/core/enums
 48797d6c34dd9bb8a53f7f3794c85f4288d82a9a1d6be7fcf317d388cb20d4b3  lib/core/replication.py
 3574639db4942d16a2dc0a2f04bb7c0913c40c3862b54d34c44075a760e0c194  lib/core/revision.py
 888daba83fd4a34e9503fe21f01fef4cc730e5cde871b1d40e15d4cbc847d56c  lib/core/session.py
-3b56bc9e795809f99cf502cc0f0c1c5b046f03720a6fd43192add592c5e90fdd  lib/core/settings.py
+b30135d16324a48ad69bd02ef6fe000b62f1afe4b99cc4f20f756256a341b916  lib/core/settings.py
 cd5a66deee8963ba8e7e9af3dd36eb5e8127d4d68698811c29e789655f507f82  lib/core/shell.py
 bcb5d8090d5e3e0ef2a586ba09ba80eef0c6d51feb0f611ed25299fbb254f725  lib/core/subprocessng.py
 d35650179816193164a5f177102f18379dfbe6bb6d40fbb67b78d907b41c8038  lib/core/target.py
@@ -209,7 +209,7 @@ c5b258be7485089fac9d9cd179960e774fbd85e62836dc67cce76cc028bb6aeb  lib/parse/hand
 4ca378496510a02c0184b45107889625dc7faf459073e83b3520c66674049af4  lib/parse/payloads.py
 80d26a30abe948faf817a14f746cc8b3e2341ea8286830cccaae253b8ac0cdff  lib/parse/sitemap.py
 1be3da334411657461421b8a26a0f2ff28e1af1e28f1e963c6c92768f9b0847c  lib/request/basicauthhandler.py
-a63147dff1fd4675c800122768d9d6564ef4b2f8f8d57abc2799c6bfe7a52c48  lib/request/basic.py
+a1c638493ecdc5194db7186bbfed815c6eed2344f2607cac8c9fa50534824266  lib/request/basic.py
 bc61bc944b81a7670884f82231033a6ac703324b34b071c9834886a92e249d0e  lib/request/chunkedhandler.py
 2daf0ce19eacda64687f441c90ef8da51714c3e8947c993ba08fb4ecdc4f5287  lib/request/comparison.py
 626bb6f3316a906a4629c0feb8ecbbcf473fb59e5bc532603c35b6b8f63f1deb  lib/request/connect.py
diff --git a/lib/core/decorators.py b/lib/core/decorators.py
index 12b60a64f..e8fbe4b6c 100644
--- a/lib/core/decorators.py
+++ b/lib/core/decorators.py
@@ -103,6 +103,17 @@ def stackedmethod(f):
     return _
 
 def lockedmethod(f):
+    """
+    Decorates a function or method with a reentrant lock (only one thread can execute the function at a time)
+
+    >>> @lockedmethod
+    ... def recursive_count(n):
+    ...     if n <= 0: return 0
+    ...     return n + recursive_count(n - 1)
+    >>> recursive_count(5)
+    15
+    """
+
     lock = threading.RLock()
 
     @functools.wraps(f)
diff --git a/lib/core/settings.py b/lib/core/settings.py
index 1fe297e88..4152e0bf8 100644
--- a/lib/core/settings.py
+++ b/lib/core/settings.py
@@ -19,7 +19,7 @@ from lib.core.enums import OS
 from thirdparty import six
 
 # sqlmap version (<major>.<minor>.<month>.<monthly commit>)
-VERSION = "1.10.1.19"
+VERSION = "1.10.1.20"
 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/lib/request/basic.py b/lib/request/basic.py
index ef8a6d2cd..758f993ca 100644
--- a/lib/request/basic.py
+++ b/lib/request/basic.py
@@ -248,6 +248,7 @@ def checkCharEncoding(encoding, warn=True):
 
     return encoding
 
+@lockedmethod
 def getHeuristicCharEncoding(page):
     """
     Returns page encoding charset detected by usage of heuristics