diff --git a/arguments.py b/arguments.py
index 12aaafe..f9160ee 100644
--- a/arguments.py
+++ b/arguments.py
@@ -1,6 +1,7 @@
 import argparse
 import os
 
+import msys
 import remote
 
 ACTION = 'action'
@@ -51,7 +52,7 @@ msys remote repository's location
 list of architectures to sync
 ''')
     sync.add_argument(f'-{SUBSYSTEMS[0]}', f'--{SUBSYSTEMS}', type=str,
-                      nargs='+', choices=remote.SUBSYSTEMS, help='''\
+                      nargs='+', choices=msys.SUBSYSTEMS, help='''\
 list of subsystems to sync
 ''')
 
@@ -61,7 +62,7 @@ list of subsystems to sync
 directory containing modifications applying to filesystem
 ''')
     build.add_argument(f'-{COMPRESSION[0]}', f'--{COMPRESSION}', type=str,
-                       choices=['7z', 'gz', 'xz', 'zst'], help='''\
+                       choices=['gz', 'xz', 'zst'], help='''\
 compression applying to archive
 ''')
 
diff --git a/msys.py b/msys.py
index b70d268..be34410 100644
--- a/msys.py
+++ b/msys.py
@@ -1,2 +1,3 @@
 ARCHIVE = '.tar.xz'
 CHARSET = 'u8'
+SUBSYSTEMS = ['msys', 'clang', 'mingw', 'ucrt']
diff --git a/remote.py b/remote.py
index 02e0052..af5468b 100644
--- a/remote.py
+++ b/remote.py
@@ -4,6 +4,7 @@ import requests
 import arguments
 import catalog
 import hypertext
+import msys
 
 
 ARCHITECTURES = ['x86_64', 'i686']
@@ -20,7 +21,6 @@ CHARSET = 'u8'
 DISTRIBUTION = 'distrib'
 MINGW = 'mingw'
 SIGNATURE = '.sig'
-SUBSYSTEMS = ['msys', 'clang', 'mingw', 'ucrt']
 
 
 class Remote:
@@ -40,7 +40,7 @@ class Remote:
             c[architecture] = {}
             for ss in self.subsystems:
                 location = self.location
-                if ss == SUBSYSTEMS[0]:
+                if ss == msys.SUBSYSTEMS[0]:
                     subsystem = ss
                     location = os.path.join(location, subsystem, architecture)
                 else: