diff --git a/bumpversion/cli.py b/bumpversion/cli.py
index b107e10d..9639b412 100644
--- a/bumpversion/cli.py
+++ b/bumpversion/cli.py
@@ -39,7 +39,7 @@
 DESCRIPTION = "{}: v{} (using Python v{})".format(
     __title__,
     __version__,
-    sys.version.split("\n")[0].split(" ")[0]
+    sys.version.split("\n", maxsplit=1)[0].split(" ", maxsplit=1)[0]
 )
 VCS = [Git, Mercurial]
 
@@ -86,12 +86,13 @@ def main(original_args=None):
     if hasattr(known_args, "config_file"):
         explicit_config = known_args.config_file
     config_file = _determine_config_file(explicit_config)
-    config, config_file_exists, config_newlines, part_configs, files = _load_configuration(
-        config_file, explicit_config, defaults,
-    )
+    config, config_file_exists, config_newlines = _load_configuration_file(config_file,
+                                                                           explicit_config,
+                                                                           defaults)
     known_args, parser2, remaining_argv = _parse_arguments_phase_2(
         args, known_args, defaults, root_parser
     )
+    part_configs, files = _load_configuration(config, defaults)
     version_config = _setup_versionconfig(known_args, part_configs)
     current_version = version_config.parse(known_args.current_version)
     context = dict(
@@ -247,7 +248,7 @@ def _determine_config_file(explicit_config):
     return ".bumpversion.cfg"
 
 
-def _load_configuration(config_file, explicit_config, defaults):
+def _load_configuration_file(config_file, explicit_config, defaults):
     # setup.cfg supports interpolation - for compatibility we must do the same.
     if os.path.basename(config_file) == "setup.cfg":
         config = ConfigParser("")
@@ -263,7 +264,7 @@ def _load_configuration(config_file, explicit_config, defaults):
         if explicit_config:
             raise argparse.ArgumentTypeError(message)
         logger.info(message)
-        return config, config_file_exists, None, {}, []
+        return config, config_file_exists, None
 
     logger.info("Reading config file %s:", config_file)
 
@@ -302,6 +303,10 @@ def _load_configuration(config_file, explicit_config, defaults):
         except NoOptionError:
             pass  # no default value then ;)
 
+    return config, config_file_exists, config_newlines
+
+
+def _load_configuration(config, defaults):
     part_configs = {}
     files = []
 
@@ -370,7 +375,7 @@ def _load_configuration(config_file, explicit_config, defaults):
                     files.append(ConfiguredFile(filename_glob, version_config))
             else:
                 files.append(ConfiguredFile(filename, version_config))
-    return config, config_file_exists, config_newlines, part_configs, files
+    return part_configs, files
 
 
 def _parse_arguments_phase_2(args, known_args, defaults, root_parser):
@@ -475,7 +480,8 @@ def _parse_arguments_phase_3(remaining_argv, positionals, defaults, parser2):
         action="store_true",
         default=False,
         dest="no_configured_files",
-        help="Only replace the version in files specified on the command line, ignoring the files from the configuration file.",
+        help="Only replace the version in files specified on the command line, "
+             "ignoring the files from the configuration file.",
     )
     parser3.add_argument(
         "--dry-run",
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 1589da01..0c250494 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -117,7 +117,7 @@ def _mock_calls_to_string(called_mock):
 [--tag-message TAG_MESSAGE]
 [--message COMMIT_MSG]
 part
-[file [file ...]]
+[file ...]
 """.strip().splitlines()
 
 EXPECTED_USAGE = (r"""
@@ -247,7 +247,7 @@ def test_defaults_in_usage_with_config(tmpdir, capsys):
     assert "New version that should be in the files (default: 19)" in out
     assert "[--current-version VERSION]" in out
     assert "[--new-version VERSION]" in out
-    assert "[file [file ...]]" in out
+    assert "[file ...]" in out
 
 
 def test_missing_explicit_config_file(tmpdir):
@@ -1261,6 +1261,42 @@ def test_multiple_serialize_two_part_patch_configfile(tmpdir):
 
     assert '0.6.1' == tmpdir.join("fileD").read()
 
+def test_serialize_via_cli_takes_priority_over_bumpversion_cfg(tmpdir):
+    tmpdir.join("fileD").write("0.6")
+    tmpdir.chdir()
+
+    tmpdir.join(".bumpversion.cfg").write(r"""[bumpversion]
+current_version = 0.6
+serialize =
+  {major}.{minor}
+parse = (?P<major>\d+)\.(?P<minor>\d+)(\.(?P<patch>\d+))?
+[bumpversion:file:fileD]
+""")
+
+    main(['minor',
+          '--serialize', '{major}.{minor}.{patch}'])
+
+    assert '0.7.0' == tmpdir.join("fileD").read()
+    assert '0.7.0' in tmpdir.join(".bumpversion.cfg").read()
+
+def test_serialize_via_cli_takes_priority_over_bumpversion_cfg_with_env_variable(tmpdir):
+    tmpdir.join("fileD").write("0.6")
+    tmpdir.chdir()
+
+    tmpdir.join(".bumpversion.cfg").write(r"""[bumpversion]
+current_version = 0.6
+serialize = {major}.{minor}
+parse = (?P<major>\d+)\.(?P<minor>\d+)(\.(?P<patch>\d+))?
+[bumpversion:file:fileD]
+""")
+
+    os.environ['BUILD_ID'] = 'pr_123'
+
+    main(['minor',
+          '--serialize', '{major}.{minor}.{patch}+{$BUILD_ID}'])
+
+    assert '0.7.0+pr_123' == tmpdir.join("fileD").read()
+    assert '0.7.0+pr_123' in tmpdir.join(".bumpversion.cfg").read()
 
 def test_search_uses_shortest_possible_custom_search_pattern(tmpdir):
     config = dedent(r"""