diff --git a/caimira/apps/expert.py b/caimira/apps/expert.py
index 111505d2..39daf3c3 100644
--- a/caimira/apps/expert.py
+++ b/caimira/apps/expert.py
@@ -12,10 +12,13 @@ from matplotlib import pyplot as plt
 import numpy as np
 import datetime
 import pandas as pd
+import logging
 
 from caimira import data, models, state
 from caimira.store.data_registry import DataRegistry
 
+LOG = logging.getLogger(__name__)
+
 
 def collapsible(widgets_to_collapse: typing.List, title: str, start_collapsed=False):
     collapsed = widgets.Accordion([widgets.VBox(widgets_to_collapse)])
@@ -929,6 +932,10 @@ class CAIMIRAStateBuilder(state.StateBuilder):
 
 class ExpertApplication(Controller):
     def __init__(self) -> None:
+        LOG.warning(
+            "ExpertApplication is deprecated and will no longer be maintained. It remains in the codebase for legacy purposes."
+        )
+
         self._data_registry = DataRegistry()
         #: A list of scenario name and ModelState instances. This is intended to be
         #: mutated. Any mutation should notify the appropriate Views for handling.
diff --git a/caimira/apps/expert_co2.py b/caimira/apps/expert_co2.py
index d083d20b..62e23f82 100644
--- a/caimira/apps/expert_co2.py
+++ b/caimira/apps/expert_co2.py
@@ -2,6 +2,7 @@ import dataclasses
 import ipywidgets as widgets
 import typing
 import numpy as np
+import logging
 
 from caimira import data, models, state
 from caimira.store.data_registry import DataRegistry
@@ -11,6 +12,8 @@ import matplotlib.lines as mlines
 import matplotlib.patches as patches
 from .expert import generate_presence_widget, collapsible, ipympl_canvas, WidgetGroup, CAIMIRAStateBuilder
 
+LOG = logging.getLogger(__name__)
+
 
 def baseline_model(data_registry: DataRegistry):
     return models.CO2ConcentrationModel(
@@ -188,6 +191,10 @@ class ExposureComparisonResult(View):
 
 class CO2Application(Controller):
     def __init__(self) -> None:
+        LOG.warning(
+            "CO2Application is deprecated and will no longer be maintained. It remains in the codebase for legacy purposes."
+        )
+
         self._data_registry = DataRegistry()
         # self._debug_output = widgets.Output()
 
diff --git a/caimira/tests/apps/test_expert_app.py b/caimira/tests/apps/test_expert_app.py
index c94f8206..85a35406 100644
--- a/caimira/tests/apps/test_expert_app.py
+++ b/caimira/tests/apps/test_expert_app.py
@@ -8,6 +8,7 @@ def expert_app():
     return caimira.apps.ExpertApplication()
 
 
+@pytest.mark.skip(reason="ExpertApplication is deprecated")
 def test_app(expert_app):
     # To start with, let's just test that the application runs. We don't try to
     # do anything fancy to verify how it looks etc., we leave that for manual
@@ -15,6 +16,7 @@ def test_app(expert_app):
     assert expert_app._model_scenarios[0][0] == "Scenario 1"
 
 
+@pytest.mark.skip(reason="ExpertApplication is deprecated")
 def test_new_scenario_changes_tab(expert_app):
     # Adding a new scenario should change the tab index of the multi-model view.
     assert expert_app.multi_model_view.widget.selected_index == 0