diff --git a/borgmatic/borg/create.py b/borgmatic/borg/create.py
index 85f7e042..f2f23c69 100644
--- a/borgmatic/borg/create.py
+++ b/borgmatic/borg/create.py
@@ -198,6 +198,7 @@ def make_base_create_command(  # noqa: PLR0912
     umask = config.get('umask', None)
     lock_wait = config.get('lock_wait', None)
     list_filter_flags = flags.make_list_filter_flags(local_borg_version, dry_run)
+    files_changed = config.get('files_changed')
     files_cache = config.get('files_cache')
     archive_name_format = (
         config.get('archive_name_format', flags.get_default_archive_name_format(local_borg_version))
@@ -248,6 +249,7 @@ def make_base_create_command(  # noqa: PLR0912
         + (('--nobirthtime',) if config.get('birthtime') is False else ())
         + (('--read-special',) if config.get('read_special') or stream_processes else ())
         + noflags_flags
+        + (('--files-changed', files_changed) if files_changed else ())
         + (('--files-cache', files_cache) if files_cache else ())
         + (('--remote-path', remote_path) if remote_path else ())
         + (('--umask', str(umask)) if umask else ())
diff --git a/borgmatic/borg/environment.py b/borgmatic/borg/environment.py
index bdadcc30..e975ec04 100644
--- a/borgmatic/borg/environment.py
+++ b/borgmatic/borg/environment.py
@@ -25,6 +25,7 @@ DEFAULT_BOOL_OPTION_TO_ENVIRONMENT_VARIABLE = {
     'relocated_repo_access_is_ok': 'BORG_RELOCATED_REPO_ACCESS_IS_OK',
     'unknown_unencrypted_repo_access_is_ok': 'BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK',
     'use_chunks_archive': 'BORG_USE_CHUNKS_ARCHIVE',
+    'msgpack_version_check': 'BORG_MSGPACK_VERSION_CHECK',
 }
 
 
@@ -90,7 +91,8 @@ def make_environment(config):
     ) in DEFAULT_BOOL_OPTION_TO_ENVIRONMENT_VARIABLE.items():
         if os.environ.get(environment_variable_name) is None:
             value = config.get(option_name)
-            environment[environment_variable_name] = 'YES' if value else 'NO'
+            if value is not None:
+                environment[environment_variable_name] = 'YES' if value else 'NO'
 
     for (
         option_name,
diff --git a/borgmatic/config/schema.yaml b/borgmatic/config/schema.yaml
index 4ddb1358..07beb241 100644
--- a/borgmatic/config/schema.yaml
+++ b/borgmatic/config/schema.yaml
@@ -166,6 +166,15 @@ properties:
             Record filesystem flags (e.g. NODUMP, IMMUTABLE) in archive.
             Defaults to true.
         example: false
+    files_changed:
+        type: string
+        enum: ['ctime', 'mtime', 'disabled']
+        description: |
+            Threshold for considering a file as changed. See
+            https://borgbackup.readthedocs.io/en/stable/usage/create.html for
+            details. Defaults to "ctime" (i.e., a file is considered
+            changed if its ctime has changed since the last backup).
+        example: ctime
     files_cache:
         type: string
         description: |
@@ -562,6 +571,12 @@ properties:
             Bypass Borg confirmation about check with repair option. Defaults to
             false and an interactive prompt from Borg.
         example: true
+    msgpack_version_check:
+        type: boolean
+        description: |
+            Optionally disable the msgpack version check.
+            Default is true; use at your own risk.
+        example: true
     extra_borg_options:
         type: object
         additionalProperties: false
diff --git a/tests/unit/borg/test_create.py b/tests/unit/borg/test_create.py
index e85b1479..969b707e 100644
--- a/tests/unit/borg/test_create.py
+++ b/tests/unit/borg/test_create.py
@@ -482,6 +482,7 @@ def test_make_base_create_command_with_store_config_false_omits_config_files():
         ('flags', True, False, ()),
         ('flags', False, True, ('--noflags',)),
         ('flags', False, False, ('--nobsdflags',)),
+        ('files_changed', 'mtime', True, ('--files-changed', 'mtime')),
         ('files_cache', 'ctime,size', True, ('--files-cache', 'ctime,size')),
         ('umask', 740, True, ('--umask', '740')),
         ('lock_wait', 5, True, ('--lock-wait', '5')),
diff --git a/tests/unit/borg/test_environment.py b/tests/unit/borg/test_environment.py
index f458cf6a..1b49ba7c 100644
--- a/tests/unit/borg/test_environment.py
+++ b/tests/unit/borg/test_environment.py
@@ -90,11 +90,6 @@ def test_make_environment_without_configuration_sets_certain_environment_variabl
     assert environment == {
         'USER': 'root',
         'BORG_EXIT_CODES': 'modern',
-        'BORG_RELOCATED_REPO_ACCESS_IS_OK': 'NO',
-        'BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK': 'NO',
-        'BORG_USE_CHUNKS_ARCHIVE': 'NO',
-        'BORG_DEBUG_PASSPHRASE': 'NO',
-        'BORG_DISPLAY_PASSPHRASE': 'NO',
     }
 
 
@@ -107,6 +102,7 @@ def test_make_environment_without_configuration_passes_through_default_environme
             'BORG_USE_CHUNKS_ARCHIVE': 'yup',
             'BORG_DEBUG_PASSPHRASE': 'nah',
             'BORG_DISPLAY_PASSPHRASE': 'yup',
+            'BORG_MSGPACK_VERSION_CHECK': 'yup',
         },
     )
     flexmock(module.borgmatic.hooks.credential.parse).should_receive(
@@ -122,6 +118,7 @@ def test_make_environment_without_configuration_passes_through_default_environme
         'BORG_USE_CHUNKS_ARCHIVE': 'yup',
         'BORG_DEBUG_PASSPHRASE': 'nah',
         'BORG_DISPLAY_PASSPHRASE': 'yup',
+        'BORG_MSGPACK_VERSION_CHECK': 'yup',
         'BORG_EXIT_CODES': 'modern',
     }