diff --git a/Cargo.lock b/Cargo.lock
index ed14c3fc..c8737215 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1008,6 +1008,12 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d231b230927b5e4ad203db57bbcbee2802f6bce620b1e4a9024a07d94e2907ec"
 
+[[package]]
+name = "portable-atomic"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7170ef9988bc169ba16dd36a7fa041e5c4cbeb6a35b76d4c03daded371eae7c0"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"
@@ -1131,9 +1137,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3"
-version = "0.20.2"
+version = "0.20.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a89dc7a5850d0e983be1ec2a463a171d20990487c3cfcd68b5363f1ee3d6fe0"
+checksum = "53bdbb96d49157e65d45cc287af5f32ffadd5f4761438b527b055fb0d4bb8233"
 dependencies = [
  "anyhow",
  "cfg-if",
@@ -1141,6 +1147,7 @@ dependencies = [
  "libc",
  "memoffset",
  "parking_lot",
+ "portable-atomic",
  "pyo3-build-config",
  "pyo3-ffi",
  "pyo3-macros",
@@ -1149,9 +1156,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-build-config"
-version = "0.20.2"
+version = "0.20.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "07426f0d8fe5a601f26293f300afd1a7b1ed5e78b2a705870c5f30893c5163be"
+checksum = "deaa5745de3f5231ce10517a1f5dd97d53e5a2fd77aa6b5842292085831d48d7"
 dependencies = [
  "once_cell",
  "target-lexicon",
@@ -1159,9 +1166,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-ffi"
-version = "0.20.2"
+version = "0.20.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dbb7dec17e17766b46bca4f1a4215a85006b4c2ecde122076c562dd058da6cf1"
+checksum = "62b42531d03e08d4ef1f6e85a2ed422eb678b8cd62b762e53891c05faf0d4afa"
 dependencies = [
  "libc",
  "pyo3-build-config",
@@ -1169,9 +1176,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros"
-version = "0.20.2"
+version = "0.20.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05f738b4e40d50b5711957f142878cfa0f28e054aa0ebdfc3fd137a843f74ed3"
+checksum = "7305c720fa01b8055ec95e484a6eca7a83c841267f0dd5280f0c8b8551d2c158"
 dependencies = [
  "proc-macro2",
  "pyo3-macros-backend",
@@ -1181,12 +1188,13 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros-backend"
-version = "0.20.2"
+version = "0.20.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0fc910d4851847827daf9d6cdd4a823fbdaab5b8818325c5e97a86da79e8881f"
+checksum = "7c7e9b68bb9c3149c5b0cade5d07f953d6d125eb4337723c4ccdb665f1f96185"
 dependencies = [
  "heck",
  "proc-macro2",
+ "pyo3-build-config",
  "quote",
  "syn 2.0.50",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 5a607980..5ad25764 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,7 @@ name = "sourmash_plugin_branchwater"
 crate-type = ["cdylib"]
 
 [dependencies]
-pyo3 = { version = "0.20.2", features = ["extension-module", "anyhow"] }
+pyo3 = { version = "0.20.3", features = ["extension-module", "anyhow"] }
 rayon = "1.8.1"
 serde = { version = "1.0.196", features = ["derive"] }
 sourmash = { version = "0.13.0", features = ["branchwater"] }