diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 48f1b3b..b012af3 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -8,7 +8,7 @@ on:
       - "master"
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: [3.7, 3.8, 3.9, "3.10"]
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fee551e..fd5f254 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Release History
 
-## 1.4.0 - 2022-02-06
+## 1.4.1 - 2022-02-06
 
 * fix: freezing pylama version to avoid breaking changes
 * feat: option to pass custom domain for AS2 message-id generation
diff --git a/pyas2lib/cms.py b/pyas2lib/cms.py
index 01bc008..0172980 100644
--- a/pyas2lib/cms.py
+++ b/pyas2lib/cms.py
@@ -1,19 +1,19 @@
 """Define functions related to the CMS operations such as encrypting, signature, etc."""
 import hashlib
 import zlib
-from collections import OrderedDict
 from datetime import datetime, timezone
 
 from asn1crypto import cms, core, algos
+from asn1crypto.cms import SMIMECapabilityIdentifier
 from oscrypto import asymmetric, symmetric, util
 
+from pyas2lib.constants import DIGEST_ALGORITHMS
 from pyas2lib.exceptions import (
     AS2Exception,
     DecompressionError,
     DecryptionError,
     IntegrityError,
 )
-from pyas2lib.constants import DIGEST_ALGORITHMS
 from pyas2lib.utils import normalize_digest_alg
 
 
@@ -277,68 +277,6 @@ def sign_message(
         digest_func.update(data_to_sign)
         message_digest = digest_func.digest()
 
-        class SmimeCapability(core.Sequence):
-            """Define the possible list of Smime Capability."""
-
-            _fields = [
-                ("0", core.Any, {"optional": True}),
-                ("1", core.Any, {"optional": True}),
-                ("2", core.Any, {"optional": True}),
-                ("3", core.Any, {"optional": True}),
-                ("4", core.Any, {"optional": True}),
-            ]
-
-        class SmimeCapabilities(core.Sequence):
-            """Define the Smime Capabilities supported by pyas2."""
-
-            _fields = [
-                ("0", SmimeCapability),
-                ("1", SmimeCapability, {"optional": True}),
-                ("2", SmimeCapability, {"optional": True}),
-                ("3", SmimeCapability, {"optional": True}),
-                ("4", SmimeCapability, {"optional": True}),
-                ("5", SmimeCapability, {"optional": True}),
-            ]
-
-        smime_cap = OrderedDict(
-            [
-                (
-                    "0",
-                    OrderedDict(
-                        [("0", core.ObjectIdentifier("2.16.840.1.101.3.4.1.42"))]
-                    ),
-                ),
-                (
-                    "1",
-                    OrderedDict(
-                        [("0", core.ObjectIdentifier("2.16.840.1.101.3.4.1.2"))]
-                    ),
-                ),
-                (
-                    "2",
-                    OrderedDict([("0", core.ObjectIdentifier("1.2.840.113549.3.7"))]),
-                ),
-                (
-                    "3",
-                    OrderedDict(
-                        [
-                            ("0", core.ObjectIdentifier("1.2.840.113549.3.2")),
-                            ("1", core.Integer(128)),
-                        ]
-                    ),
-                ),
-                (
-                    "4",
-                    OrderedDict(
-                        [
-                            ("0", core.ObjectIdentifier("1.2.840.113549.3.4")),
-                            ("1", core.Integer(128)),
-                        ]
-                    ),
-                ),
-            ]
-        )
-
         signed_attributes = cms.CMSAttributes(
             [
                 cms.CMSAttribute(
@@ -376,8 +314,34 @@ class SmimeCapabilities(core.Sequence):
                 cms.CMSAttribute(
                     {
                         "type": cms.CMSAttributeType("1.2.840.113549.1.9.15"),
-                        "values": cms.SetOfAny(
-                            [core.Any(SmimeCapabilities(smime_cap))]
+                        "values": cms.SetOfSMIMECapabilites(
+                            [
+                                cms.SMIMECapabilites(
+                                    [
+                                        SMIMECapabilityIdentifier(
+                                            {"capability_id": "2.16.840.1.101.3.4.1.42"}
+                                        ),
+                                        SMIMECapabilityIdentifier(
+                                            {"capability_id": "2.16.840.1.101.3.4.1.2"}
+                                        ),
+                                        SMIMECapabilityIdentifier(
+                                            {"capability_id": "1.2.840.113549.3.7"}
+                                        ),
+                                        SMIMECapabilityIdentifier(
+                                            {
+                                                "capability_id": "1.2.840.113549.3.2",
+                                                "parameters": core.Integer(128),
+                                            }
+                                        ),
+                                        SMIMECapabilityIdentifier(
+                                            {
+                                                "capability_id": "1.2.840.113549.3.4",
+                                                "parameters": core.Integer(128),
+                                            }
+                                        ),
+                                    ]
+                                )
+                            ]
                         ),
                     }
                 ),
diff --git a/setup.py b/setup.py
index 71bda72..f111d11 100644
--- a/setup.py
+++ b/setup.py
@@ -1,8 +1,8 @@
 from setuptools import setup, find_packages
 
 install_requires = [
-    "asn1crypto==1.4.0",
-    "oscrypto==1.2.1",
+    "asn1crypto==1.5.1",
+    "oscrypto==1.3.0",
     "pyOpenSSL==21.0.0",
 ]
 
@@ -16,6 +16,7 @@
     "pylama-pylint==3.1.1",
     "black==22.6.0",
     "pytest-black==0.3.12",
+    "pyflakes==2.4.0",
 ]
 
 setup(