diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4eb008e..2915995 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,30 @@
+# 1.0
+
+  - Add Unix diff style annotations to output of `prettyContextDiff`,
+    e.g `@@ -1,5 +1,4 @@`.  This required three changes to the
+    signature of `getContextDiff` due to the addition of a wrapper type
+    `Numbered`, which enumerates the elements of the input list.
+
+  - Signature change 1: The element pretty printer type changes from
+    `(a -> Doc)` to `(Numbered a -> Doc)`.  An unnumber function is
+    provided so that the old behavior can be obtained by changing that
+    argument from `pretty` to `(pretty . unnumber)`
+
+  - Signature change 2: The result type of getContextDiff changes from
+    `ContextDiff a` to `ContextDiff (Numbered a)`.  A function
+    `unNumberContextDiff` is provided to convert the result back to
+    the old type.
+
+  - Signature change 3: the context argument is now `Maybe Int` rather
+    than `Int`, reflecting the change made to `getContextDiffNew` in 0.5.
+
+  - A `prettyContextDiffOld` function is provided to get the old
+    style output.
+
+  - The old broken version of getContextDiffOld is removed.
+
+  - Document the behavior of `groupBy'`.
+
 # 0.5
 
   - Bring space complexity down to D^2 (Bodigrim).
diff --git a/Diff.cabal b/Diff.cabal
index a10cdc2..8d6d1e9 100644
--- a/Diff.cabal
+++ b/Diff.cabal
@@ -1,4 +1,4 @@
-Cabal-Version:       >= 1.18
+Cabal-Version:       1.18
 name:                Diff
 version:             1.0
 synopsis:            Diff algorithm in pure Haskell