diff --git a/src/pat/recurrence/README.md b/src/pat/recurrence/README.md
index c926ec4f3..5bc964ae5 100644
--- a/src/pat/recurrence/README.md
+++ b/src/pat/recurrence/README.md
@@ -16,8 +16,54 @@ Show the recurrence widget.
 
 ## Example
 
-<textarea class="pat-recurrence"></textarea>
+### Recurrence without additional start feature
+
+<label>Recurrence start date:
+<input name="start-1" type="date" value="2026-01-01"/>
+</label>
+<label>Recurrence:
+<textarea
+    class="pat-recurrence"
+    data-pat-recurrence='{
+        "startField": "[name=start-2]"
+    }'></textarea>
+</label>
+
+```html
+<textarea
+    class="pat-recurrence"
+    data-pat-recurrence='{
+        "startField": "[name=start-2]"
+    }'
+></textarea>
+```
+
+### Recurrence with additional start feature
+
+Note: adding additional start dates is a feature of the specification but is
+not supported by a number of external tools, like Google Calendar, Microsoft
+Outlook or Gnome Calendar.
+Therefore, this feature is disabled by default.
+However, you can enable it with the `hasAdditionalDates` feature.
+
+<label>Recurrence start date:
+<input name="start-2" type="date" value="2026-01-01"/>
+</label>
+<label>Recurrence:
+<textarea
+    class="pat-recurrence"
+    data-pat-recurrence='{
+        "startField": "[name=start-2]",
+        "hasAdditionalDates": true
+    }'></textarea>
+</label>
 
 ```html
-<textarea class="pat-recurrence"></textarea>
+<textarea
+    class="pat-recurrence"
+    data-pat-recurrence='{
+        "startField": "[name=start-2]",
+        "hasAdditionalDates": true
+    }'
+></textarea>
 ```
diff --git a/src/pat/recurrence/recurrence.js b/src/pat/recurrence/recurrence.js
index 80b883ebc..6fe02ae21 100644
--- a/src/pat/recurrence/recurrence.js
+++ b/src/pat/recurrence/recurrence.js
@@ -739,7 +739,6 @@ const RecurrenceInput = function (conf, textarea) {
         }
 
         occurrenceDiv = element.find(".rioccurrences");
-        occurrenceDiv.hide();
 
         const year = startdate.getFullYear();
         const month = startdate.getMonth() + 1;
@@ -811,11 +810,11 @@ const RecurrenceInput = function (conf, textarea) {
                         .find(".rioccurrences .action a.rdate")
                         .on("click", occurrenceDelete);
                 }
-                // Show the new div
-                occurrenceDiv.show();
             },
-            error: function (jqXHR, textStatus) {
-                alert(textStatus);
+            error: function () {
+                occurrenceDiv[0].innerHTML = `
+                  <div class="alert alert-warning">${conf.localization.error_load_occurrences}</div>
+                `;
             },
         });
     }
@@ -1377,6 +1376,8 @@ export default Base.extend({
                 monthly: "Monthly",
                 yearly: "Yearly",
             },
+
+            error_load_occurrences: "Cannot load the occurrences preview.",
         },
 
         readOnly: false,
@@ -1392,6 +1393,7 @@ export default Base.extend({
         ributtonExtraClass: "",
 
         // INPUT CONFIGURATION
+        hasAdditionalDates: false,
         hasRepeatForeverButton: true,
 
         // JQUERY TEMPLATE NAMES
diff --git a/src/pat/recurrence/recurrence.test.js b/src/pat/recurrence/recurrence.test.js
index 521807dea..c227979ec 100644
--- a/src/pat/recurrence/recurrence.test.js
+++ b/src/pat/recurrence/recurrence.test.js
@@ -28,4 +28,71 @@ describe("Recurrence", function () {
         ).toEqual("none");
         expect(document.querySelector("div.riform").style.display).toEqual("none");
     });
+
+    it("Adds a warning, if the occurrences preview cannot be loaded.", async function () {
+        // Without any test mock server, the occurrences preview cannot be loaded.
+        document.body.innerHTML = `
+            <input name="start" type="date" value="2026-01-01" />
+            <textarea class="pat-recurrence"
+                      data-pat-recurrence='{
+                          "startField": "[name=start]"
+                      }'
+            ></textarea>
+        `;
+
+        registry.scan(document.body);
+        await utils.timeout(1);
+
+        const edit_btn = document.querySelector("[name=riedit]");
+        edit_btn.click();
+
+        const occurrences_preview = document.querySelector(
+            ".rioccurrences .alert-warning",
+        );
+        expect(occurrences_preview).toBeTruthy();
+        expect(occurrences_preview.textContent.trim()).toBe(
+            "Cannot load the occurrences preview.",
+        );
+    });
+
+    it("Initializes without the additional dates feature.", async function () {
+        document.body.innerHTML = `
+            <input name="start" type="date" value="2026-01-01" />
+            <textarea class="pat-recurrence"
+                      data-pat-recurrence='{
+                          "startField": "[name=start]"
+                      }'
+            ></textarea>
+        `;
+
+        registry.scan(document.body);
+        await utils.timeout(1);
+
+        const edit_btn = document.querySelector("[name=riedit]");
+        edit_btn.click();
+
+        const add_occurrence = document.querySelector(".modal .riaddoccurrence");
+        expect(add_occurrence).toBeFalsy();
+    });
+
+    it("Initializes with the additional dates feature.", async function () {
+        document.body.innerHTML = `
+            <input name="start" type="date" value="2026-01-01" />
+            <textarea class="pat-recurrence"
+                      data-pat-recurrence='{
+                          "startField": "[name=start]",
+                          "hasAdditionalDates": true
+                      }'
+            ></textarea>
+        `;
+
+        registry.scan(document.body);
+        await utils.timeout(1);
+
+        const edit_btn = document.querySelector("[name=riedit]");
+        edit_btn.click();
+
+        const add_occurrence = document.querySelector(".modal .riaddoccurrence");
+        expect(add_occurrence).toBeTruthy();
+    });
 });
diff --git a/src/pat/recurrence/templates/form.xml b/src/pat/recurrence/templates/form.xml
index d3db8cf9c..fe55aba56 100644
--- a/src/pat/recurrence/templates/form.xml
+++ b/src/pat/recurrence/templates/form.xml
@@ -291,6 +291,7 @@
         <div class="rioccurrences"></div>
 
         <div class="rioccurrencesactions">
+            <% if (hasAdditionalDates === true) { %>
             <h6><strong><%= localization.addDate %></strong></h6>
             <div class="riaddoccurrence ">
                 <div class="alert alert-danger d-none"></div>
@@ -299,6 +300,7 @@
                     <input class="btn btn-sm btn-success" type="button" name="addaction" id="addaction" value="<%= localization.add %>">
                 </div>
             </div>
+            <% } %>
         </div>
 
         <div class="ributtons">