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3.0-Upgrade.md

@@ -11,11 +11,10 @@ guide](https://guides.rubyonrails.org/caching_with_rails.html#activesupport-cach
 * Compression now defaults to `true` for large values (greater than 4KB).
   This is intended to minimize errors due to the previous note.
 * Errors marshalling values now raise rather than just printing an error.
-* The Rack session adapter has been removed. Users should [vendor the
-  session adapter code in 2.7](https://github.com/petergoldstein/dalli/blob/2.x/lib/) or
-  switch to an alternative session adapter, like Redis or cookie.
-* Support for the high-performance `kgio` gem has been removed, as it is
-  no longer relevant in Ruby 2.3+.
+* The Rack session adapter has been refactored to remove support for thread-unsafe
+  configurations. You will need to include the `connection_pool` gem in
+  your Gemfile to ensure session operations are thread-safe.
+* Support for the `kgio` gem has been removed, it is not relevant in Ruby 2.3+.
 * Removed inline native code, use Ruby 2.3+ support for bsearch instead.
 * The CAS operations previously in 'dalli/cas/client' have been
   integrated into 'dalli/client'.