diff --git a/duty_board/alchemy/update_duty_calendars.py b/duty_board/alchemy/update_duty_calendars.py
index 7e09212..ab420e2 100644
--- a/duty_board/alchemy/update_duty_calendars.py
+++ b/duty_board/alchemy/update_duty_calendars.py
@@ -1,5 +1,6 @@
 import datetime
-from typing import List
+import json
+from typing import List, Union
 
 from pendulum.tz.timezone import UTC
 from sqlalchemy import delete, select
@@ -11,6 +12,7 @@
 
 def _create_or_update_calendar(session: SASession, calendar: DutyCalendarConfig) -> None:
     calendar_db_instance = session.scalars(select(Calendar).where(Calendar.uid == calendar.uid)).one_or_none()
+    extra_info_serialized: Union[None, str] = json.dumps(calendar.extra_info) if calendar.extra_info else None
     if calendar_db_instance is not None:
         calendar_db_instance.name = calendar.name
         calendar_db_instance.description = calendar.description
@@ -18,6 +20,7 @@ def _create_or_update_calendar(session: SASession, calendar: DutyCalendarConfig)
         calendar_db_instance.order = calendar.order
         calendar_db_instance.icalendar_url = calendar.icalendar_url
         calendar_db_instance.event_prefix = calendar.event_prefix
+        calendar_db_instance.extra_info = extra_info_serialized
         session.merge(calendar_db_instance)
     else:
         calendar_db_instance = Calendar(
@@ -28,6 +31,7 @@ def _create_or_update_calendar(session: SASession, calendar: DutyCalendarConfig)
             order=calendar.order,
             icalendar_url=calendar.icalendar_url,
             event_prefix=calendar.event_prefix,
+            extra_info=extra_info_serialized,
             error_msg=None,
             last_update_utc=datetime.datetime(1970, 1, 1, 0, 0, 0, tzinfo=UTC),
             sync=True,
diff --git a/duty_board/models/calendar.py b/duty_board/models/calendar.py
index 5a2aead..729ccb2 100644
--- a/duty_board/models/calendar.py
+++ b/duty_board/models/calendar.py
@@ -20,7 +20,6 @@ class Calendar(Base):
     order: Mapped[int]
     icalendar_url: Mapped[str] = mapped_column(String(500), nullable=False)
     event_prefix: Mapped[Optional[str]] = mapped_column(String(50), nullable=True)
-    # The `extra_info` can be used to store information that we can use in the plugin.
     extra_info: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
     error_msg: Mapped[Optional[str]] = mapped_column(
         String(9999),
diff --git a/duty_board/plugin/helpers/duty_calendar_config.py b/duty_board/plugin/helpers/duty_calendar_config.py
index 1d25c59..5fc62f5 100644
--- a/duty_board/plugin/helpers/duty_calendar_config.py
+++ b/duty_board/plugin/helpers/duty_calendar_config.py
@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Dict, Optional, Union
 
 from pydantic import BaseModel, Field
 from typing_extensions import Annotated
@@ -20,3 +20,5 @@ class DutyCalendarConfig(BaseModel):
     order: Annotated[int, Field(default=99999, ge=0, le=9999999)]
     # Prefix before user LDAP or user email is mentioned. Example prefix; 'duty:' when calendar event; 'duty: thomas'
     event_prefix: Annotated[Optional[str], Field(max_length=50, default=None)]
+    # The extra_info can be used to store information that we can use in the plugin.
+    extra_info: Optional[Dict[str, Union[int, float, str]]]