Remove old versionadded/versionchanged notes

docs/advanced_topics/images/custom_image_model.rst

@@ -47,10 +47,6 @@ Here's an example:
             )
 
 
-.. versionchanged:: 1.10
-
-    In previous versions of Wagtail it was necessary to connect signal handlers to handle deletion of image files. As of Wagtail 1.10 this is now handled automatically.
-
 .. note::
 
     Fields defined on a custom image model must either be set as non-required

docs/reference/contrib/frontendcache.rst

@@ -203,8 +203,6 @@ For example, this could be useful for purging a single page on a blog index:
 The ``PurgeBatch`` class
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
-.. versionadded:: 1.13
-
 All of the methods available on ``PurgeBatch`` are listed below:
 
 .. automodule:: wagtail.contrib.frontend_cache.utils