| A | ↘ | B | BaseCollection got worse |
| ⇢ | A | BaseCollection::offsetUnset() added | |
| ⇢ | A | BaseCollection::offsetSet() added | |
| ⇢ | A | BaseCollection::offsetExists() added | |
| ⇢ | A | BaseCollection::offsetGet() added | |
| A | ↛ | Collection::offsetSet() removed | |
| A | ↛ | Collection::offsetUnset() removed | |
| A | ↛ | Collection::offsetExists() removed | |
| A | ↛ | Collection::offsetGet() removed |