diff --git a/.gitignore b/.gitignore
index 6e2c5498e..fd4f52364 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 
 *.icloud
+Pipfile.lock
 
 out
 *.js
diff --git a/.vscode/settings.json b/.vscode/settings.json
index d961b0e7e..bf7f61ae1 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -288,6 +288,7 @@
         "sysconf",
         "tbitem",
         "tbody",
+        "tbtrim",
         "tcif",
         "tclass",
         "tcls",
diff --git a/Pipfile b/Pipfile
index fdc410b15..55be90a84 100644
--- a/Pipfile
+++ b/Pipfile
@@ -9,6 +9,7 @@ aenum = "*"
 setuptools = "*"
 dictdumper = "*"
 emoji = "*"
+tbtrim = "*"
 
 [dev-packages]
 pcapkit = {editable = true, path = "."}
diff --git a/setup.py b/setup.py
index 1723c24fe..96c33636c 100644
--- a/setup.py
+++ b/setup.py
@@ -6,7 +6,7 @@
     from distutils.core import setup
 
 # version string
-__version__ = '0.13.0.post2'
+__version__ = '0.13.1'
 
 # README
 with open('README.md', encoding='utf-8') as file:
@@ -28,7 +28,13 @@
     python_requires='>=3.4',
     include_package_data=True,
     zip_safe=True,
-    install_requires=['dictdumper', 'chardet', 'aenum', 'emoji'],
+    install_requires=[
+        'dictdumper',   # for formatted output
+        'chardet',      # for bytes decode
+        'aenum',        # for const types
+        'emoji',        # for CLI display
+        'tbtrim',       # for refined exceptions
+    ],
     extras_require={
         'all': ['dpkt', 'scapy', 'pyshark'],
         'DPKT': ['dpkt'],
diff --git a/src/__init__.py b/src/__init__.py
index 5665b9314..df60b7a5e 100644
--- a/src/__init__.py
+++ b/src/__init__.py
@@ -53,6 +53,11 @@
     dump utilities for `pcapkit` implementation
 
 """
+# set up sys.excepthook
+import os
+import tbtrim
+tbtrim.set_trim_rule(lambda filename: f'{os.path.sep}pcapkit{os.path.sep}' in filename)
+
 # All Reference
 import pcapkit.__all__ as all  # pylint: disable
 
diff --git a/src/corekit/protochain.py b/src/corekit/protochain.py
index f3accdc6b..ff2567f11 100644
--- a/src/corekit/protochain.py
+++ b/src/corekit/protochain.py
@@ -11,6 +11,7 @@
 import re
 
 from pcapkit.corekit.infoclass import Info
+from pcapkit.utilities.compat import Collection
 from pcapkit.utilities.exceptions import (IndexNotFound, IntError,
                                           ProtocolUnbound)
 from pcapkit.utilities.validations import int_check, str_check
@@ -22,7 +23,7 @@
 __all__ = ['ProtoChain']
 
 
-class _ProtoList(collections.abc.Collection):
+class _ProtoList(Collection):
     """List of protocol classes for ProtoChain."""
     @property
     def data(self):
diff --git a/src/foundation/extraction.py b/src/foundation/extraction.py
index 0d1847cfd..56c053f29 100644
--- a/src/foundation/extraction.py
+++ b/src/foundation/extraction.py
@@ -27,6 +27,7 @@
 from pcapkit.corekit.infoclass import Info
 from pcapkit.protocols.pcap.frame import Frame
 from pcapkit.protocols.pcap.header import Header
+from pcapkit.utilities.compat import pathlib
 from pcapkit.utilities.exceptions import (CallableError, FileNotFound,
                                           FormatError, IterableError,
                                           UnsupportedCall, stacklevel)
@@ -34,11 +35,6 @@
                                         EngineWarning, FormatWarning,
                                         LayerWarning, ProtocolWarning)
 
-try:
-    import pathlib2 as pathlib
-except ImportError:
-    import pathlib
-
 ###############################################################################
 # import enum
 # import multiprocessing
diff --git a/src/foundation/traceflow.py b/src/foundation/traceflow.py
index 3570aeb7f..62ed8a9f0 100644
--- a/src/foundation/traceflow.py
+++ b/src/foundation/traceflow.py
@@ -12,15 +12,11 @@
 import warnings
 
 from pcapkit.corekit.infoclass import Info
+from pcapkit.utilities.compat import pathlib
 from pcapkit.utilities.exceptions import FileExists, stacklevel
 from pcapkit.utilities.validations import pkt_check
 from pcapkit.utilities.warnings import FileWarning, FormatWarning
 
-try:
-    import pathlib2 as pathlib
-except ImportError:
-    import pathlib
-
 ###############################################################################
 # from dictdumper import JSON, PLIST, XML, JavaScript, Tree
 # from pcapkit.dumpkit import PCAP, NotImplementedIO
diff --git a/src/utilities/__init__.py b/src/utilities/__init__.py
index 3a219ba48..fc38b4270 100644
--- a/src/utilities/__init__.py
+++ b/src/utilities/__init__.py
@@ -7,6 +7,7 @@
 user-refined exceptions and validations.
 
 """
+from pcapkit.utilities.compat import *
 from pcapkit.utilities.decorators import *
 from pcapkit.utilities.exceptions import *
 from pcapkit.utilities.validations import *
diff --git a/src/utilities/compat.py b/src/utilities/compat.py
new file mode 100644
index 000000000..d2c6f645a
--- /dev/null
+++ b/src/utilities/compat.py
@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+
+import builtins
+import collections.abc
+import sys
+
+__all__ = [
+    'ModuleNotFoundError',  # exceptions
+    'Collection',           # classes
+    'pathlib',              # modules
+]
+
+if sys.version_info[:2] < (3, 6):
+    class ModuleNotFoundError(ImportError):
+        pass
+else:
+    ModuleNotFoundError = builtins.ModuleNotFoundError
+
+if sys.version_info[:2] <= (3, 5):
+    def _check_methods(C, *methods):
+        mro = C.__mro__
+        for method in methods:
+            for B in mro:
+                if method in B.__dict__:
+                    if B.__dict__[method] is None:
+                        return NotImplemented
+                    break
+            else:
+                return NotImplemented
+        return True
+
+    class Collection(collections.abc.Sized, collections.abc.Iterable, collections.abc.Container):
+
+        __slots__ = ()
+
+        @classmethod
+        def __subclasshook__(cls, C):
+            if cls is Collection:
+                return _check_methods(C,  "__len__", "__iter__", "__contains__")
+            return NotImplemented
+else:
+    Collection = collections.abc.Collection
+
+if sys.version_info[:2] <= (3, 4):
+    import pathlib2 as pathlib
+else:
+    import pathlib
diff --git a/src/utilities/exceptions.py b/src/utilities/exceptions.py
index 721fd991c..3aa210bfc 100644
--- a/src/utilities/exceptions.py
+++ b/src/utilities/exceptions.py
@@ -11,6 +11,8 @@
 import sys
 import traceback
 
+from pcapkit.utilities.compat import ModuleNotFoundError
+
 __all__ = [
     'BaseError',                                                    # Exception
     'DigitError', 'IntError', 'RealError', 'ComplexError',          # TypeError