diff --git a/exam-server/main.py b/exam-server/main.py
index ca997d27..eafd6ae9 100644
--- a/exam-server/main.py
+++ b/exam-server/main.py
@@ -38,6 +38,9 @@ def update_cache():
     with open("static/index.html") as f:
         main_html = f.read()
 
+        if getenv("ENV") == "dev":
+            main_html = main_html.replace("production.min", "development")
+
     with open("static/main.js") as f:
         main_js = f.read()
 
diff --git a/examtool/examtool/api/convert.py b/examtool/examtool/api/convert.py
index fec6b86d..6a423c92 100644
--- a/examtool/examtool/api/convert.py
+++ b/examtool/examtool/api/convert.py
@@ -9,7 +9,7 @@
 
 from examtool.api.utils import list_to_dict, IDFactory
 
-VERSION = 2  # increment when backward-incompatible changes are made
+VERSION = 3  # increment when backward-incompatible changes are made
 
 
 def html_convert(x):
diff --git a/examtool/examtool/api/scramble.py b/examtool/examtool/api/scramble.py
index 937352cb..bc778c25 100644
--- a/examtool/examtool/api/scramble.py
+++ b/examtool/examtool/api/scramble.py
@@ -46,7 +46,7 @@ def scramble_group_children():
                 )
         get_elements(group)[:] = elements
 
-        if version > 1:
+        if version >= 2:
             scramble_group_children()
 
         if is_compressible_group(group):
@@ -62,6 +62,8 @@ def scramble_group_children():
                 out.append(element)
             return out
 
+        add_entropy(group)
+
         return [group]
 
     def scramble_question(question, substitutions, config):
@@ -100,6 +102,8 @@ def scramble_question(question, substitutions, config):
         else:
             question.pop("solution", None)
 
+        add_entropy(question)
+
         return question
 
     def substitute(target: dict, list_substitutions, attrs, *, store=True):
@@ -137,6 +141,10 @@ def scramble_keep_fixed(objects):
         for i, object in zip(movable_object_pos, movable_object_values):
             objects[i] = object
 
+    def add_entropy(element):
+        if version >= 3:
+            element["entropy"] = hex(random.randrange(2 ** 30))
+
     global_substitutions = select_substitutions(exam)
     exam["config"]["scramble_groups"] = exam["config"].get(
         "scramble_groups", [-1]
diff --git a/examtool_web_common/js/ElementEntropy.js b/examtool_web_common/js/ElementEntropy.js
new file mode 100644
index 00000000..7500140d
--- /dev/null
+++ b/examtool_web_common/js/ElementEntropy.js
@@ -0,0 +1,11 @@
+import React from "react";
+
+export default function ElementEntropy({ entropy }) {
+  return (
+    entropy != null && (
+      <small style={{ color: "gray", marginTop: -5 }}>
+        [version {entropy}]
+      </small>
+    )
+  );
+}
diff --git a/examtool_web_common/js/Exam.js b/examtool_web_common/js/Exam.js
index 378f6c30..0c428549 100644
--- a/examtool_web_common/js/Exam.js
+++ b/examtool_web_common/js/Exam.js
@@ -4,6 +4,7 @@ import { typeset } from "MathJax";
 import { Col, Jumbotron, Row } from "react-bootstrap";
 import Anchor from "./Anchor";
 import { inAdminMode } from "./auth";
+import ElementEntropy from "./ElementEntropy";
 import ExamContext from "./ExamContext";
 import Points from "./Points";
 import Question from "./Question";
@@ -94,6 +95,7 @@ export function Group({ group, number, small }) {
         <Points points={group.points} />
         {/* eslint-disable-next-line react/no-danger */}
         <div dangerouslySetInnerHTML={{ __html: group.html }} />
+        <ElementEntropy entropy={group.entropy} />
         {group.elements.map((element, i) =>
           element.type === "group" ? (
             <Group
diff --git a/examtool_web_common/js/Question.js b/examtool_web_common/js/Question.js
index df712257..9384a091 100644
--- a/examtool_web_common/js/Question.js
+++ b/examtool_web_common/js/Question.js
@@ -10,6 +10,7 @@ import { Form, FormControl, InputGroup } from "react-bootstrap";
 import Anchor from "./Anchor";
 import { getAuthParams } from "./auth";
 import debounce from "./debounce";
+import ElementEntropy from "./ElementEntropy";
 import ExamContext from "./ExamContext";
 import FailText from "./FailText";
 import LoadingButton from "./LoadingButton";
@@ -264,6 +265,7 @@ export default function Question({ question, number }) {
             style={{ marginTop: 8 }}
             dangerouslySetInnerHTML={{ __html: question.html }}
           />
+          <ElementEntropy entropy={question.entropy} />
         </Form.Label>
         {contents}
         <LoadingButton
diff --git a/examtool_web_common/js/Timer.js b/examtool_web_common/js/Timer.js
index 17a48b4a..ab9f2096 100644
--- a/examtool_web_common/js/Timer.js
+++ b/examtool_web_common/js/Timer.js
@@ -7,7 +7,7 @@ export default function Timer({ target, onLock, onEnd }) {
   const [hover, setHover] = useState(false);
   const [timeString, setTimeString] = useState("");
 
-  const updateTimeString = () => {
+  const updateTimeString = (initial) => {
     const time = Math.round(new Date().getTime() / 1000);
     const remaining = Math.max(target - time, 0);
 
@@ -21,20 +21,22 @@ export default function Timer({ target, onLock, onEnd }) {
         .padStart(2, "0")}:${seconds.toString().padStart(2, "0")}`
     );
 
-    if (target - time < 0 && target - time >= -60) {
-      onLock();
-      setTimeString(`${60 + target - time}s`);
-    }
+    if (!initial) {
+      if (target - time < 0 && target - time >= -60) {
+        onLock();
+        setTimeString(`${60 + target - time}s`);
+      }
 
-    if (target - time < -60) {
-      onEnd();
+      if (target - time < -60) {
+        onEnd();
+      }
     }
   };
 
   useInterval(updateTimeString, 1000);
 
   if (!timeString) {
-    updateTimeString();
+    updateTimeString(true);
   }
 
   return (