diff --git a/imap/http_caldav_sched.c b/imap/http_caldav_sched.c
index 0b8eddfbfa..196f913462 100644
--- a/imap/http_caldav_sched.c
+++ b/imap/http_caldav_sched.c
@@ -622,7 +622,7 @@ static int imip_send(const char *cal_ownerid, const char *sched_userid,
             /* Updated event */
             json_t *new_jsevent = jmapical_tojmap(sched_data->newical, NULL, NULL);
 
-            patch = jmap_patchobject_create(jsevent, new_jsevent);
+            patch = jmap_patchobject_create(jsevent, new_jsevent, 0/*no_remove*/);
             json_decref(new_jsevent);
         }
         else {
diff --git a/imap/jmap_calendar.c b/imap/jmap_calendar.c
index 01c4876c8d..4d7a1be659 100644
--- a/imap/jmap_calendar.c
+++ b/imap/jmap_calendar.c
@@ -4857,7 +4857,7 @@ static void updateevent_apply_patch_override(struct jmap_caleventid *eid,
     json_object_del(new_instance, "recurrenceRules");
     json_object_del(new_instance, "recurrenceOverrides");
     json_object_del(new_instance, "excludedRecurrenceRules");
-    new_override = jmap_patchobject_create(old_event, new_instance);
+    new_override = jmap_patchobject_create(old_event, new_instance, 0/*no_remove*/);
     json_object_del(new_override, "@type");
     json_object_del(new_override, "method");
     json_object_del(new_override, "prodId");
@@ -4999,7 +4999,7 @@ static void updateevent_apply_patch_event(json_t *old_event,
                 continue;
             }
             /* Diff updated override */
-            json_t *new_override = jmap_patchobject_create(new_event, jval);
+            json_t *new_override = jmap_patchobject_create(new_event, jval, 0/*no_remove*/);
             if (!new_override) continue;
             json_object_set_new(new_overrides, recurid, new_override);
         }
@@ -5114,7 +5114,7 @@ static void updateevent_bump_sequence(json_t *old_event,
 
     /* ... a non per-user property got updated */
     int updates_shared_prop = 0;
-    json_t *jpatch = jmap_patchobject_create(old_event, new_event);
+    json_t *jpatch = jmap_patchobject_create(old_event, new_event, 0/*no_remove*/);
     const char *path;
     json_t *jval;
     void *tmp;
diff --git a/imap/jmap_ical.c b/imap/jmap_ical.c
index 23ccf9faca..c227b46243 100644
--- a/imap/jmap_ical.c
+++ b/imap/jmap_ical.c
@@ -2095,7 +2095,7 @@ overrides_from_ical(icalcomponent *comp, ptrarray_t *icaloverrides,
         }
 
         /* Create override patch */
-        json_t *diff = jmap_patchobject_create(event, ex);
+        json_t *diff = jmap_patchobject_create(event, ex, 0/*no_remove*/);
         json_object_del(diff, "@type");
         json_object_del(diff, "uid");
         json_object_del(diff, "relatedTo");
diff --git a/imap/jmap_notif.c b/imap/jmap_notif.c
index 4ab7689115..324c78dadf 100644
--- a/imap/jmap_notif.c
+++ b/imap/jmap_notif.c
@@ -386,7 +386,7 @@ HIDDEN int jmap_create_caldaveventnotif(struct transaction_t *txn,
         if (newical) {
             type = "updated";
             json_t *tmp = jmapical_tojmap(newical, NULL, NULL);
-            jpatch = jmap_patchobject_create(jevent, tmp);
+            jpatch = jmap_patchobject_create(jevent, tmp, 0/*no_remove*/);
             json_decref(tmp);
         }
         else type = "destroyed";
diff --git a/imap/jmap_util.c b/imap/jmap_util.c
index 8fdf1b0d9a..0d8032fdec 100644
--- a/imap/jmap_util.c
+++ b/imap/jmap_util.c
@@ -213,7 +213,7 @@ static void jmap_patchobject_set(json_t *diff, struct buf *path,
 }
 
 static void jmap_patchobject_diff(json_t *diff, struct buf *path,
-                                  json_t *src, json_t *dst)
+                                  json_t *src, json_t *dst, int no_remove)
 {
     if (!json_is_object(src) || !json_is_object(dst))
         return;
@@ -228,10 +228,12 @@ static void jmap_patchobject_diff(json_t *diff, struct buf *path,
         }
     }
 
-    // Remove any properties that are set in src but not in dst
-    json_object_foreach(src, key, val) {
-        if (json_object_get(dst, key) == NULL) {
-            jmap_patchobject_set(diff, path, key, json_null());
+    if (!no_remove) {
+        // Remove any properties that are set in src but not in dst
+        json_object_foreach(src, key, val) {
+            if (json_object_get(dst, key) == NULL) {
+                jmap_patchobject_set(diff, path, key, json_null());
+            }
         }
     }
 
@@ -254,19 +256,19 @@ static void jmap_patchobject_diff(json_t *diff, struct buf *path,
             size_t len = buf_len(path);
             if (len) buf_appendcstr(path, "/");
             buf_appendcstr(path, enckey);
-            jmap_patchobject_diff(diff, path, srcval, val);
+            jmap_patchobject_diff(diff, path, srcval, val, no_remove);
             buf_truncate(path, len);
             free(enckey);
         }
     }
 }
 
-EXPORTED json_t *jmap_patchobject_create(json_t *src, json_t *dst)
+EXPORTED json_t *jmap_patchobject_create(json_t *src, json_t *dst, int no_remove)
 {
     json_t *diff = json_object();
     struct buf buf = BUF_INITIALIZER;
 
-    jmap_patchobject_diff(diff, &buf, src, dst);
+    jmap_patchobject_diff(diff, &buf, src, dst, no_remove);
 
     buf_free(&buf);
     return diff;
diff --git a/imap/jmap_util.h b/imap/jmap_util.h
index 1f32af1c52..901b8dba16 100644
--- a/imap/jmap_util.h
+++ b/imap/jmap_util.h
@@ -71,7 +71,7 @@ extern int jmap_readprop_full(json_t *root, const char *prefix, const char *name
 extern json_t* jmap_patchobject_apply(json_t *val, json_t *patch, json_t *invalid);
 
 /* Create a patch-object that transforms src into dst. */
-extern json_t *jmap_patchobject_create(json_t *src, json_t *dst);
+extern json_t *jmap_patchobject_create(json_t *src, json_t *dst, int no_remove);
 
 /* Return non-zero src and its RFC 6901 encoding differ */
 extern int jmap_pointer_needsencode(const char *src);