diff --git a/ipython-kernel.cabal b/ipython-kernel.cabal
--- a/ipython-kernel.cabal
+++ b/ipython-kernel.cabal
@@ -1,5 +1,5 @@
 name:                ipython-kernel
-version:             0.10.3.0
+version:             0.11.0.0
 synopsis:            A library for creating kernels for IPython frontends
 
 description:         ipython-kernel is a library for communicating with frontends for the interactive IPython framework. It is used extensively in IHaskell, the interactive Haskell environment.
diff --git a/src/IHaskell/IPython/Types.hs b/src/IHaskell/IPython/Types.hs
--- a/src/IHaskell/IPython/Types.hs
+++ b/src/IHaskell/IPython/Types.hs
@@ -40,13 +40,13 @@
 
 import           Data.Aeson
 import           Data.Aeson.Types (typeMismatch)
+import           Data.Binary
 import           Data.ByteString (ByteString)
 import           Data.List (find)
 import           Data.Map (Map)
 import qualified Data.Map as Map
 import           Data.Maybe (fromMaybe)
 import           Data.Semigroup (Semigroup)
-import           Data.Binary
 import           Data.Text (Text, pack)
 import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Text
@@ -920,7 +920,7 @@
 
 -- | Data for display: a string with associated MIME type.
 data DisplayData = DisplayData MimeType Text
-  deriving (Typeable, Generic)
+  deriving (Typeable, Eq, Generic)
 
 -- We can't print the actual data, otherwise this will be printed every time it gets computed
 -- because of the way the evaluator is structured. See how `displayExpr` is computed.