diff --git a/c/CHANGELOG.rst b/c/CHANGELOG.rst
index 4daf2132f9..ddf5e2f252 100644
--- a/c/CHANGELOG.rst
+++ b/c/CHANGELOG.rst
@@ -1,3 +1,9 @@
+--------------------
+[1.3.3] - 2027-XX-XX
+--------------------
+
+In development
+
 --------------------
 [1.3.2] - 2026-10-30
 --------------------
diff --git a/python/CHANGELOG.rst b/python/CHANGELOG.rst
index ee9bf8a2cf..dace3aada3 100644
--- a/python/CHANGELOG.rst
+++ b/python/CHANGELOG.rst
@@ -1,3 +1,9 @@
+--------------------
+[1.0.5] - 2027-XX-XX
+--------------------
+
+In development
+
 --------------------
 [1.0.4] - 2026-10-30
 --------------------
diff --git a/python/tskit/_version.py b/python/tskit/_version.py
index 12358aa06c..c27c716dd7 100644
--- a/python/tskit/_version.py
+++ b/python/tskit/_version.py
@@ -1,4 +1,4 @@
 # Definitive location for the version number.
 # During development, should be x.y.z.devN
 # For beta should be x.y.zbN
-tskit_version = "1.0.4"
+tskit_version = "1.0.5.dev1"