diff --git a/CHANGELOG.md b/CHANGELOG.md
index adba7e1..db890ea 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,16 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/), 
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Mortimer v0.8.12 (Released 2021-10-28)
+
+### Added
+
+- Added support for alfred3's new test mode
+- Added "sid" prefix for session ids
+- Added quickstart options for alfred3's test mode and debug mode
+- Added a warning that will appear upon codebook download if element 
+  labels in *the two newest* datasets are unequal.
+
 ## Mortimer v0.8.11 (Released 2021-10-14)
 
 ### Changed
diff --git a/src/mortimer/_version.py b/src/mortimer/_version.py
index 27ad00e..0c5e4de 100644
--- a/src/mortimer/_version.py
+++ b/src/mortimer/_version.py
@@ -4,4 +4,5 @@
 # 3) we can import it into your module module
 
 
-__version__ = "0.8.11"
+
+__version__ = "0.8.12"
diff --git a/src/mortimer/templates/experiment.html b/src/mortimer/templates/experiment.html
index d0bfedc..d2d9852 100644
--- a/src/mortimer/templates/experiment.html
+++ b/src/mortimer/templates/experiment.html
@@ -30,18 +30,34 @@ <h1>{{ experiment.title }}</h1>
         </div>
       </div>
 
-      <div class="form-row mb-3 justify-content-end">
-      <div class="col col-sm-8">
-      <small class="text-muted pl-2">You can use the field and button below to start your experiment with url parameters, for example: <code>param1=value1&amp;param2=value2</code></small>
-      <div class="input-group pl-2">
-      <input type="text" class="form-control" placeholder="param=value" value="{{ experiment.urlparam }}" id="start_param">
-      <div class="input-group-append">
-      <button class="btn btn-primary" type="button" id="start_with_param">
-      <i class="fas fa-play mr-2"></i>Start with parameters
-      </button>
-      </div>
-      </div>
+      <div class="input-group mb-3">
+        <input type="text" class="form-control" aria-describedby="basic-addon2" id="link-to-exp-test"
+          value="{{ url_for('alfredo.start', expid=expid, _external=True) }}?test=true">
+        <div class="input-group-append">
+          <button class="btn btn-outline-secondary" type="button" data-clipboard-target="#link-to-exp-test">
+            <img src="{{ url_for('static', filename='clippy.svg')}}" alt="Copy to clipboard" width="20"> Copy Link
+          </button>
+          <a class="btn btn-dark" target="_blank" rel="noopener noreferrer"
+            href="{{ url_for('alfredo.start', expid=expid) }}?test=true"><i class="fas fa-play mr-2"></i>Test</a>
+          <a class="btn btn-info" target="_blank" rel="noopener noreferrer"
+            href="{{ url_for('alfredo.start', expid=expid) }}?debug=true"><i class="fas fa-play mr-2"></i>Debug</a>
+        </div>
       </div>
+
+      <div class="form-row mb-3 justify-content-end">
+        <div class="col col-sm-8">
+          <small class="text-muted pl-2">You can use the field and button below to start your experiment with url
+            parameters, for example: <code>param1=value1&amp;param2=value2</code></small>
+          <div class="input-group pl-2">
+            <input type="text" class="form-control" placeholder="param=value" value="{{ experiment.urlparam }}"
+              id="start_param">
+            <div class="input-group-append">
+              <button class="btn btn-primary" type="button" id="start_with_param">
+                <i class="fas fa-play mr-2"></i>Start with parameters
+              </button>
+            </div>
+          </div>
+        </div>
       </div>
 
 
@@ -67,6 +83,36 @@ <h1>{{ experiment.title }}</h1>
         </div>
       </div>
 
+      <div class="input-group mb-3">
+        <input type="text" class="form-control" aria-describedby="basic-addon2" id="link-to-exp-test"
+          value="{{ url_for('alfredo.start', expid=expid, _external=True) }}?test=true">
+        <div class="input-group-append">
+          <button class="btn btn-outline-secondary" type="button" data-clipboard-target="#link-to-exp-test">
+            <img src="{{ url_for('static', filename='clippy.svg')}}" alt="Copy to clipboard" width="20"> Copy Link
+          </button>
+          <a class="btn btn-dark" target="_blank" rel="noopener noreferrer"
+            href="{{ url_for('alfredo.start', expid=expid) }}?test=true"><i class="fas fa-play mr-2"></i>Test</a>
+          <a class="btn btn-info" target="_blank" rel="noopener noreferrer"
+            href="{{ url_for('alfredo.start', expid=expid) }}?debug=true"><i class="fas fa-play mr-2"></i>Debug</a>
+        </div>
+      </div>
+
+      <div class="form-row mb-3 justify-content-end">
+        <div class="col col-sm-8">
+          <small class="text-muted pl-2">You can use the field and button below to start your experiment with url
+            parameters, for example: <code>param1=value1&amp;param2=value2</code></small>
+          <div class="input-group pl-2">
+            <input type="text" class="form-control" placeholder="param=value" value="{{ experiment.urlparam }}"
+              id="start_param">
+            <div class="input-group-append">
+              <button class="btn btn-primary" type="button" id="start_with_param">
+                <i class="fas fa-play mr-2"></i>Start with parameters
+              </button>
+            </div>
+          </div>
+        </div>
+      </div>
+
       {% endif %}
     </div>
   </div>
@@ -341,14 +387,16 @@ <h5 class="modal-title" id="uploadModalLabel">Upload script.py</h5>
 
 <script>
   var starturl = "{{ url_for('alfredo.start', expid=expid, _external=True) }}"
-  var updateurl = "{{ url_for('web_experiments.update_urlparam', experiment_title=experiment.title, username=experiment.author, _external=True) }}"
-
-$( "#start_with_param" ).click(function() {
-  var startparam = $( "#start_param" ).val();
-  var targeturl = starturl + "?" + startparam;
-  $.post( updateurl, {urlparam: startparam} );
-  window.open(targeturl).focus();
-});
-
+  var updateurl =
+    "{{ url_for('web_experiments.update_urlparam', experiment_title=experiment.title, username=experiment.author, _external=True) }}"
+
+  $("#start_with_param").click(function () {
+    var startparam = $("#start_param").val();
+    var targeturl = starturl + "?" + startparam;
+    $.post(updateurl, {
+      urlparam: startparam
+    });
+    window.open(targeturl).focus();
+  });
 </script>
 {% endblock %}
\ No newline at end of file
diff --git a/src/mortimer/web_experiments/alfredo.py b/src/mortimer/web_experiments/alfredo.py
index e61bdff..a73a8f5 100644
--- a/src/mortimer/web_experiments/alfredo.py
+++ b/src/mortimer/web_experiments/alfredo.py
@@ -162,7 +162,7 @@ def start(expid):
     experiment = WebExperiment.objects.get_or_404(id=ObjectId(expid))
 
     # create session id
-    sid = str(uuid4())
+    sid = "sid-" + str(uuid4())
 
     config = experiment.parse_exp_config(sid)
     secrets = experiment.parse_exp_secrets()
@@ -178,7 +178,10 @@ def start(expid):
             % exp_url
         )
     
-    if not experiment.active:
+    args = request.args.to_dict()
+    test_mode = args.get("test") in ["true", "True", "TRUE"]
+    debug_mode = args.get("debug") in ["true", "True", "TRUE"] or config.getboolean("general", "debug")
+    if not experiment.active and not test_mode and not debug_mode:
         return render_template("exp_inactive.html")
 
     session["sid"] = sid
diff --git a/src/mortimer/web_experiments/routes.py b/src/mortimer/web_experiments/routes.py
index 8376c65..f646a4b 100644
--- a/src/mortimer/web_experiments/routes.py
+++ b/src/mortimer/web_experiments/routes.py
@@ -780,7 +780,26 @@ def export_codebook_data(username, experiment_title, delim: str, version: str):
     # combine them to a single dictionary, overwriting old values 
     # with newer ones
     data = {}
-    for entry in cbdata_collection:
+    n = len(cbdata_collection)
+    for i, entry in enumerate(cbdata_collection):
+        
+        # check if all labels in the last two data sets match
+        if i == n-1 and data:
+            for name, cb in entry.items():
+                for lab in ["label_top", "label_left", "label_right", "label_bottom", "placeholder"]:
+                    old = data.get(name, "")
+                    oldlab = old.get(lab, "") if old else ""
+                    newlab = cb.get(lab, "")
+                    if not oldlab == newlab:
+                        flash(
+                            (
+                                f"Codebook: {lab} of '{name}' has changed from '{oldlab}' to '{newlab}'. "
+                                "This introduces inconsistencies into the codebook. "
+                                "Do you have dynamic labels that do not match their elements' names? "
+                                "To change a label, increase the experiment version."
+                            ),
+                            "warning"
+                        )
         data.update(entry)
 
     fieldnames = data_manager.DataManager.extract_fieldnames(data.values())