diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4f7c8739..d783cda9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 1.0.0 / 2019-10-15
+
+_This release does not support the storage format of v0.5–v0.9 anymore. Only persistence files created by v0.10+ are usable. Upgrade to v0.10 first to convert existing persistence files._
+
+[CHANGE] Remove code to convert the legacy v0.5–v0.9 storage format.
+
 ## 0.10.0 / 2019-10-10
 
 _This release changes the storage format. v0.10 can read the storage format of v0.5–v0.9. It will then persist the new format so that a downgrade won't be possible anymore._
diff --git a/VERSION b/VERSION
index 78bc1abd..3eefcb9d 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.10.0
+1.0.0