diff --git a/UPGRADE-2.1.md b/UPGRADE-2.1.md
index aa57ba7ef8..02ae5ea3a3 100644
--- a/UPGRADE-2.1.md
+++ b/UPGRADE-2.1.md
@@ -536,25 +536,43 @@
* In the choice field type's template, the `_form_is_choice_selected` method
used to identify a selected choice has been replaced with the `selectedchoice`
- filter.
+ filter. Similarly, the `_form_is_choice_group` method used to check if a
+ choice is grouped has been removed and can be checked with the `iterable`
+ test.
Before:
```
{% for choice, label in choices %}
-
+ {% if _form_is_choice_group(label) %}
+
+ {% else %}
+
+ {% endif %}
{% endfor %}
```
After:
```
- {% for choice, label in choices %}
-
+ {% for label, choice in choices %}
+ {% if choice is iterable %}
+
+ {% else %}
+
+ {% endif %}
{% endfor %}
```