diff --git a/caimira/apps/templates/about.html.j2 b/caimira/apps/templates/about.html.j2
index 28140cc1..c503c1bb 100644
--- a/caimira/apps/templates/about.html.j2
+++ b/caimira/apps/templates/about.html.j2
@@ -15,7 +15,7 @@ CAiMIRA stands for CERN Airborne Model for Indoor Risk Assessment, previously kn
 Since then, the model has evolved and now is capable of simulating the short-range component. CAiMIRA comes with different applications that allow more or less flexibility in the input parameters:
 <ul>
 	<li><a href='{{ get_calculator_url() }}'>CAiMIRA calculator app</a></li>
-	<li><a href='/expert-app'>CAiMIRA expert app</a></li>
+	<li><a href='{{ get_url() }}/expert-app'>CAiMIRA expert app</a></li>
 </ul>
 
 The mathematical and physical model simulate the airborne spread of SARS-CoV-2 virus in a finite volume, assuming a homogenous mixture and a two-stage exhaled jet model, and estimates the risk of COVID-19 airborne transmission therein. The results DO NOT include other known modes of SARS-CoV-2 transmission. Hence, the output from this model is only valid when the other recommended public health & safety instructions are observed, such as good hand hygiene and other barrier measures.<br>
diff --git a/caimira/apps/templates/base/index.html.j2 b/caimira/apps/templates/base/index.html.j2
index 65f19037..d7c432a3 100644
--- a/caimira/apps/templates/base/index.html.j2
+++ b/caimira/apps/templates/base/index.html.j2
@@ -32,7 +32,7 @@
         <div class="d-flex flex-row" >
           <div class="pr-3"><a href="{{ get_calculator_url() }}" role="button" class="btn btn-lg btn-outline-primary"><div class="d-flex d-row"><i class="icon-calculator"></i><span class="pl-2">Calculator</div></a></div>
           <br>
-          <div class="expert_app_button"><a href="/expert-app" role="button" class="btn btn-lg btn-outline-secondary"><div class="d-flex d-row"><i class="icon-expert"></i><span class="pl-2">Expert app</div></a></div>
+          <div class="expert_app_button"><a href="{{ get_url() }}/expert-app" role="button" class="btn btn-lg btn-outline-secondary"><div class="d-flex d-row"><i class="icon-expert"></i><span class="pl-2">Expert app</div></a></div>
         </div>
         <br>
       </div>
@@ -46,7 +46,7 @@
   <div class="split">
     <div class="w-25 mobile-sub-section"><hr width="95%">
       <div class="d-flex m-2 align-items-center"><i class="bi bi-window" style="font-size: 25px"></i><div><p class="paragraph-title ml-2">Applications</p></div></div>
-      <div class="m-2">CAiMIRA is composed of two applications, the <a href="{{ get_calculator_url() }}">Calculator</a> and the <a href="/expert-app">Expert App</a>.</div>
+      <div class="m-2">CAiMIRA is composed of two applications, the <a href="{{ get_calculator_url() }}">Calculator</a> and the <a href="{{ get_url() }}/expert-app">Expert App</a>.</div>
     </div>
     <div class="w-25 mobile-sub-section"><hr width="95%">
       <div class="d-flex m-2 align-items-center"><i class="bi bi-info-square-fill" style="font-size: 25px"></i><div><p class="paragraph-title ml-2">About</p></div></div>
diff --git a/caimira/apps/templates/base/layout.html.j2 b/caimira/apps/templates/base/layout.html.j2
index 5ea37537..e64664bd 100644
--- a/caimira/apps/templates/base/layout.html.j2
+++ b/caimira/apps/templates/base/layout.html.j2
@@ -45,8 +45,8 @@
               <ul class="dropdown-menu dropwown-navbar-colors" style="min-width: 12rem;" aria-labelledby="navbarDropdown">
                 <li><a href="{{ get_calculator_url() }}" class="{{ "header-navbar nav-link active" if "calculator/" == active_page else "header-navbar nav-link" }}">Calculator</a></li>
                 <li><div class="d-flex"><span class="d-flex align-self-center submenu-division"></span><a href="{{ get_calculator_url() }}/user-guide" class="{{ "header-navbar nav-link active" if "user-guide" in active_page else "header-navbar nav-link" }}">User Guide</a></div></li>
-                <li><a href="/expert-app" class="{{ "header-navbar nav-link active" if "/expert-app" == active_page else "header-navbar nav-link" }}">Expert app</a></li>
-                <li><a href="/co2-app" class="{{ "header-navbar nav-link active" if "/co2-app" == active_page else "header-navbar nav-link" }}">CO₂ Simulator</a></li>
+                <li><a href="{{ get_url() }}/expert-app" class="{{ "header-navbar nav-link active" if "{{ get_url() }}/expert-app" == active_page else "header-navbar nav-link" }}">Expert app</a></li>
+                <li><a href="{{ get_url() }}/expert-app" class="{{ "header-navbar nav-link active" if "{{ get_url() }}/expert-app" == active_page else "header-navbar nav-link" }}">CO₂ Simulator</a></li>
               </ul>
             </li>
           </div>
diff --git a/caimira/apps/templates/expert-app.html.j2 b/caimira/apps/templates/expert-app.html.j2
new file mode 100644
index 00000000..5b779440
--- /dev/null
+++ b/caimira/apps/templates/expert-app.html.j2
@@ -0,0 +1,18 @@
+{% extends "base/layout.html.j2" %}
+
+{% block main %}
+
+<div class="container container--padding" style="word-wrap:break-word";> 
+
+<h1 class="paragraph-title">CAiMIRA Expert Apps were deprecated in version 5.16.0</h1><br>
+
+With the latest feature implementations in the core CAiMIRA engine, the <b>ExpertApplication</b> and <b>CO2Application</b> apps are no longer actively maintained.
+For legacy purposes, the source code is still available in the <a href="https://gitlab.cern.ch/caimira/caimira/">GitLab</a> repository.
+<br><br>
+For any query, please let us know by sending an email to <a href="mailto:CAiMIRA-dev@cern.ch">CAiMIRA-dev@cern.ch</a>.
+<br><br>
+<div class="pr-3"><a href="{{ get_calculator_url() }}" role="button" class="btn btn-lg btn-outline-primary"><div class="d-flex d-row"><i class="icon-calculator"></i><span class="pl-2">Calculator</div></a></div>
+
+</div>
+
+{% endblock main %}
\ No newline at end of file