diff --git a/src/backend/matrix_client.py b/src/backend/matrix_client.py
index 91101ec3..64bb6392 100644
--- a/src/backend/matrix_client.py
+++ b/src/backend/matrix_client.py
@@ -40,7 +40,7 @@ from .errors import (
 from .html_markdown import HTML_PROCESSOR as HTML
 from .media_cache import Media, Thumbnail
 from .models.items import (
-    Account, Event, Member, Presence, Room, Upload, UploadStatus, ZeroDate,
+    Account, Event, Member, Presence, Room, Upload, UploadStatus, ZERO_DATE,
 )
 from .models.model_store import ModelStore
 from .nio_callbacks import NioCallbacks
@@ -1397,7 +1397,7 @@ class MatrixClient(nio.AsyncClient):
             model.clear()
 
         self.models[self.user_id, "rooms"][room_id].last_event_date = \
-            ZeroDate
+            ZERO_DATE
 
 
     async def devices_info(self) -> List[Dict[str, Any]]:
@@ -1431,7 +1431,7 @@ class MatrixClient(nio.AsyncClient):
                 "id":                device.id,
                 "display_name":      device.display_name or "",
                 "last_seen_ip":      (device.last_seen_ip or "").strip(" -"),
-                "last_seen_date":    device.last_seen_date or ZeroDate,
+                "last_seen_date":    device.last_seen_date or ZERO_DATE,
                 "last_seen_country": "",
                 "type":              get_type(device.id),
                 "ed25519_key":       get_ed25519(device.id),
diff --git a/src/backend/models/items.py b/src/backend/models/items.py
index bfda5976..ffbb4032 100644
--- a/src/backend/models/items.py
+++ b/src/backend/models/items.py
@@ -15,9 +15,11 @@ import nio
 from ..utils import AutoStrEnum, auto
 from .model_item import ModelItem
 
-ZeroDate              = datetime.fromtimestamp(0)
 OptionalExceptionType = Union[Type[None], Type[Exception]]
-PresenceOrder: Dict[str, int] = {
+
+ZERO_DATE = datetime.fromtimestamp(0)
+
+PRESENCE_ORDER: Dict[str, int] = {
     "online":      0,
     "unavailable": 1,
     "offline":     2,
@@ -76,12 +78,12 @@ class Presence:
         echo_invisible   = auto()
 
         def __lt__(self, other: "Presence.State") -> bool:
-            return PresenceOrder[self.value] < PresenceOrder[other.value]
+            return PRESENCE_ORDER[self.value] < PRESENCE_ORDER[other.value]
 
 
     presence:         State    = State.offline
     currently_active: bool     = False
-    last_active_at:   datetime = ZeroDate
+    last_active_at:   datetime = ZERO_DATE
     status_msg:       str      = ""
 
     members: Dict[str, "Member"] = field(default_factory=dict)
@@ -131,7 +133,7 @@ class Account(ModelItem):
     display_name:     str      = ""
     avatar_url:       str      = ""
     max_upload_size:  int      = 0
-    profile_updated:  datetime = ZeroDate
+    profile_updated:  datetime = ZERO_DATE
     connecting:       bool     = False
     total_unread:     int      = 0
     total_highlights: int      = 0
@@ -143,7 +145,7 @@ class Account(ModelItem):
     presence_support: bool           = False
     presence:         Presence.State = Presence.State.offline
     currently_active: bool           = False
-    last_active_at:   datetime       = ZeroDate
+    last_active_at:   datetime       = ZERO_DATE
     status_msg:       str            = ""
 
     def __lt__(self, other: "Account") -> bool:
@@ -187,7 +189,7 @@ class Room(ModelItem):
     can_set_join_rules:   bool = False
     can_set_guest_access: bool = False
 
-    last_event_date: datetime = ZeroDate
+    last_event_date: datetime = ZERO_DATE
 
     unreads:          int  = 0
     highlights:       int  = 0
@@ -273,14 +275,14 @@ class Member(ModelItem):
     typing:          bool     = False
     power_level:     int      = 0
     invited:         bool     = False
-    profile_updated: datetime = ZeroDate
+    profile_updated: datetime = ZERO_DATE
 
     last_read_event: str      = ""
-    last_read_at:    datetime = ZeroDate
+    last_read_at:    datetime = ZERO_DATE
 
     presence:         Presence.State = Presence.State.offline
     currently_active: bool           = False
-    last_active_at:   datetime       = ZeroDate
+    last_active_at:   datetime       = ZERO_DATE
     status_msg:       str            = ""
 
     def __lt__(self, other: "Member") -> bool: