diff --git a/Cargo.lock b/Cargo.lock
index 78e781b5..9168f637 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2800,7 +2800,7 @@ dependencies = [
 
 [[package]]
 name = "qcs"
-version = "0.25.5"
+version = "0.25.6-rc.0"
 dependencies = [
  "assert2",
  "async-trait",
@@ -2941,7 +2941,7 @@ dependencies = [
 
 [[package]]
 name = "qcs-sdk-python"
-version = "0.21.5"
+version = "0.21.6-rc.0"
 dependencies = [
  "async-trait",
  "numpy",
diff --git a/crates/lib/CHANGELOG.md b/crates/lib/CHANGELOG.md
index 2c640060..35c7861f 100644
--- a/crates/lib/CHANGELOG.md
+++ b/crates/lib/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.25.6-rc.0
+
+### Fixes
+
+- update rust and ci dependencies (#519)
+
 ## 0.25.5
 
 ### Features
diff --git a/crates/lib/Cargo.toml b/crates/lib/Cargo.toml
index 99d4a502..21854ff3 100644
--- a/crates/lib/Cargo.toml
+++ b/crates/lib/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "qcs"
 description = "High level interface for running Quil on a QPU"
-version = "0.25.5"
+version = "0.25.6-rc.0"
 edition = "2018"
 license = "Apache-2.0"
 repository = "https://github.com/rigetti/qcs-sdk-rust"
diff --git a/crates/python/CHANGELOG.md b/crates/python/CHANGELOG.md
index 095f62ab..9ec1e997 100644
--- a/crates/python/CHANGELOG.md
+++ b/crates/python/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.21.6-rc.0
+
+### Fixes
+
+- update rust and ci dependencies (#519)
+
 ## 0.21.5
 
 ### Features
diff --git a/crates/python/Cargo.toml b/crates/python/Cargo.toml
index 559db888..a1d8b20d 100644
--- a/crates/python/Cargo.toml
+++ b/crates/python/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "qcs-sdk-python"
 description = "Python bindings to qcs-sdk-rust"
-version = "0.21.5"
+version = "0.21.6-rc.0"
 edition = "2021"
 license = "Apache-2.0"
 repository = "https://github.com/rigetti/qcs-sdk-rust"
diff --git a/crates/python/pyproject.toml b/crates/python/pyproject.toml
index 49cee182..e1ea96af 100644
--- a/crates/python/pyproject.toml
+++ b/crates/python/pyproject.toml
@@ -1,7 +1,7 @@
 # This is the metadata Maturin uploads to PyPI on publish
 [project]
 name = "qcs-sdk-python"
-version = "0.21.5"
+version = "0.21.6-rc.0"
 description = "Python interface for the QCS Rust SDK"
 readme = "README.md"
 license = { text = "Apache-2.0" }