diff --git a/docs/config_serialization.rst b/docs/config_serialization.rst
index 976c6106..7f3049fc 100644
--- a/docs/config_serialization.rst
+++ b/docs/config_serialization.rst
@@ -7,4 +7,6 @@ Serialization
 
 From 0.7.0 the serializer is msgspec, which is configurable using ``SESSION_SERIALIZATION_FORMAT``. The default format is ``'msgpack'`` which has 30% storage reduction compared to ``'json'``. The ``'json'`` format may be helpful for debugging, easier viewing or compatibility. Switching between the two should be seamless, even for existing sessions.
 
+All sessions that are accessed or modified while using 0.7.0 will convert to a msgspec format. Once using 1.0.0, any sessions that are still in pickle format will be cleared upon access.
+
 The msgspec library has speed and memory advantages over other libraries. However, if you want to use a different library (such as pickle or orjson), you can override the :attr:`session_interface.serializer`.