diff --git a/Cargo.lock b/Cargo.lock
index c7aee897..33b37d2b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,9 +4,9 @@ version = 3
 
 [[package]]
 name = "autocfg"
-version = "1.2.0"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f1fdabc7756949593fe60f30ec81974b613357de856987752631dea1e3394c80"
+checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
 
 [[package]]
 name = "cfg-if"
@@ -14,18 +14,6 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
-[[package]]
-name = "heck"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
-
-[[package]]
-name = "indoc"
-version = "2.0.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b248f5224d1d606005e02c97f5aa4e88eeb230488bcc03bc9ca4d7991399f2b5"
-
 [[package]]
 name = "libc"
 version = "0.2.153"
@@ -53,38 +41,26 @@ version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7170ef9988bc169ba16dd36a7fa041e5c4cbeb6a35b76d4c03daded371eae7c0"
 
-[[package]]
-name = "proc-macro2"
-version = "1.0.86"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e719e8df665df0d1c8fbfd238015744736151d4445ec0836b8e628aae103b77"
-dependencies = [
- "unicode-ident",
-]
-
 [[package]]
 name = "pyo3"
-version = "0.22.0"
+version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1962a33ed2a201c637fc14a4e0fd4e06e6edfdeee6a5fede0dab55507ad74cf7"
+checksum = "4e99090d12f6182924499253aaa1e73bf15c69cea8d2774c3c781e35badc3548"
 dependencies = [
  "cfg-if",
- "indoc",
  "libc",
  "memoffset",
  "once_cell",
  "portable-atomic",
  "pyo3-build-config",
  "pyo3-ffi",
- "pyo3-macros",
- "unindent",
 ]
 
 [[package]]
 name = "pyo3-build-config"
-version = "0.22.0"
+version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab7164b2202753bd33afc7f90a10355a719aa973d1f94502c50d06f3488bc420"
+checksum = "7879eb018ac754bba32cb0eec7526391c02c14a093121857ed09fbf1d1057d41"
 dependencies = [
  "once_cell",
  "target-lexicon",
@@ -92,80 +68,23 @@ dependencies = [
 
 [[package]]
 name = "pyo3-ffi"
-version = "0.22.0"
+version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c6424906ca49013c0829c5c1ed405e20e2da2dc78b82d198564880a704e6a7b7"
+checksum = "ce2baa5559a411fc1cf519295f24c34b53d5d725818bc96b5abf94762da09041"
 dependencies = [
  "libc",
  "pyo3-build-config",
 ]
 
-[[package]]
-name = "pyo3-macros"
-version = "0.22.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "82b2f19e153122d64afd8ce7aaa72f06a00f52e34e1d1e74b6d71baea396460a"
-dependencies = [
- "proc-macro2",
- "pyo3-macros-backend",
- "quote",
- "syn",
-]
-
-[[package]]
-name = "pyo3-macros-backend"
-version = "0.22.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd698c04cac17cf0fe63d47790ab311b8b25542f5cb976b65c374035c50f1eef"
-dependencies = [
- "heck",
- "proc-macro2",
- "pyo3-build-config",
- "quote",
- "syn",
-]
-
-[[package]]
-name = "quote"
-version = "1.0.35"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "291ec9ab5efd934aaf503a6466c5d5251535d108ee747472c3977cc5acc868ef"
-dependencies = [
- "proc-macro2",
-]
-
-[[package]]
-name = "syn"
-version = "2.0.68"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "901fa70d88b9d6c98022e23b4136f9f3e54e4662c3bc1bd1d84a42a9a0f0c1e9"
-dependencies = [
- "proc-macro2",
- "quote",
- "unicode-ident",
-]
-
 [[package]]
 name = "target-lexicon"
 version = "0.12.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e1fc403891a21bcfb7c37834ba66a547a8f402146eba7265b5a6d88059c9ff2f"
 
-[[package]]
-name = "unicode-ident"
-version = "1.0.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
-
-[[package]]
-name = "unindent"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7de7d73e1754487cb58364ee906a499937a0dfabd86bcb980fa99ec8c8fa2ce"
-
 [[package]]
 name = "whenever"
-version = "0.6.4"
+version = "0.1.0"
 dependencies = [
  "pyo3",
  "pyo3-build-config",
diff --git a/Cargo.toml b/Cargo.toml
index b8690da5..3521026d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "whenever"
-version = "0.6.4"
+version = "0.1.0"  # Dummy value. Isn't actually used in distribution of the Python package
 authors = []
 description = "Rust extension module for whenever"
 edition = "2021"
@@ -22,16 +22,14 @@ include = [
 name = "_whenever"
 crate-type = ["cdylib", "rlib"]
 
-[features]
-extension-module = ["pyo3/extension-module"]
-
 [[bench]]
 name = "benchmarks"
 path = "benchmarks/rust/main.rs"
 
 [dependencies]
 pyo3-ffi = { version = "^0.22.0", default-features = false, features = ["extension-module"]}
-pyo3 = { version = "^0.22.0", features = ["extension-module"] }
+# FUTURE: can we remove this? Currently seems we cannot configure setuptools-rust without it
+pyo3 = { version = "^0.22.0", default-features = false, features = ["extension-module"] }
 
 [build-dependencies]
 pyo3-build-config = { version = "^0.22.0" }
diff --git a/pyproject.toml b/pyproject.toml
index 50c175f2..b0c0589c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ authors = [
     {name = "Arie Bovenberg", email = "a.c.bovenberg@gmail.com"},
 ]
 readme = "README.md"
-version = "0.6.4"
+version = "0.6.4rc0"
 description = "Modern datetime library for Python, written in Rust"
 requires-python = ">=3.9"
 classifiers = [
diff --git a/pysrc/whenever/_pywhenever.py b/pysrc/whenever/_pywhenever.py
index 85f35ff8..c08b4274 100644
--- a/pysrc/whenever/_pywhenever.py
+++ b/pysrc/whenever/_pywhenever.py
@@ -32,7 +32,7 @@
 #   - It saves some overhead
 from __future__ import annotations
 
-__version__ = "0.6.4"
+__version__ = "0.6.4rc0"
 
 import enum
 import re