diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,15 @@
+0.9.0
+=====
+
+This version changes the way `Float` and `Double` are serialized to a
+more compact format. Old data should be migrated automatically. As a
+result, however, the `Float` and `Double` data serialized by this version can not be read
+by older versions of `safecopy`.
+
+This change originated as a modification to the way `cereal` 0.5 serializes `Float` and `Double`.
+
+[https://github.com/GaloisInc/cereal/commit/47d839609413e3e9d1147b99c34ae421ae36bced](https://github.com/GaloisInc/cereal/commit/47d839609413e3e9d1147b99c34ae421ae36bced)
+
+[https://github.com/GaloisInc/cereal/issues/35](https://github.com/GaloisInc/cereal/issues/35)
+
+
diff --git a/safecopy.cabal b/safecopy.cabal
--- a/safecopy.cabal
+++ b/safecopy.cabal
@@ -7,7 +7,7 @@
 -- The package version. See the Haskell package versioning policy
 -- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
 -- standards guiding when and how versions should be incremented.
-Version:             0.9.0
+Version:             0.9.0.1
 
 -- A short (one-line) description of the package.
 Synopsis:            Binary serialization with version control.
@@ -37,7 +37,7 @@
 
 -- Extra files to be distributed with the package, such as examples or
 -- a README.
--- Extra-source-files:
+Extra-source-files: CHANGELOG.md
 
 -- Constraint on the version of Cabal needed to build this package.
 Cabal-version:       >=1.8