[core] Raise minimum recommended Python version to 3.8 (#8183)

Authored by: Grub4K

yt_dlp/update.py

@@ -112,6 +112,31 @@ def is_non_updateable():
         detect_variant(), _NON_UPDATEABLE_REASONS['unknown' if VARIANT else 'other'])
 
 
+def _get_system_deprecation():
+    MIN_SUPPORTED, MIN_RECOMMENDED = (3, 7), (3, 8)
+
+    if sys.version_info > MIN_RECOMMENDED:
+        return None
+
+    major, minor = sys.version_info[:2]
+    if sys.version_info < MIN_SUPPORTED:
+        msg = f'Python version {major}.{minor} is no longer supported'
+    else:
+        msg = f'Support for Python version {major}.{minor} has been deprecated. '
+        # Temporary until `win_x86_exe` uses 3.8, which will deprecate Vista and Server 2008
+        if detect_variant() == 'win_x86_exe':
+            platform_name = platform.platform()
+            if any(platform_name.startswith(f'Windows-{name}') for name in ('Vista', '2008Server')):
+                msg = 'Support for Windows Vista/Server 2008 has been deprecated. '
+            else:
+                return None
+        msg += ('See  https://github.com/yt-dlp/yt-dlp/issues/7803  for details.'
+                '\nYou may stop receiving updates on this version at any time')
+
+    major, minor = MIN_RECOMMENDED
+    return f'{msg}! Please update to Python {major}.{minor} or above'
+
+
 def _sha256_file(path):
     h = hashlib.sha256()
     mv = memoryview(bytearray(128 * 1024))