diff --git a/Cargo.toml b/Cargo.toml
index 4f890de..aab66ad 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ license = "MIT OR Apache-2.0"
 repository = "https://github.com/Ekleog/indexed-db"
 keywords = ["wasm", "indexeddb", "async", "web", "webassembly"]
 categories = ["asynchronous", "database", "wasm", "web-programming"]
+rust-version = "1.85"
 
 [dependencies]
 futures-channel = "0.3.30"
diff --git a/README.md b/README.md
index 6da357a..16e1e30 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ async fn example() -> anyhow::Result<()> {
 
     // Open the database, creating it if needed
     let db = factory
-        .open("database", 1, |evt| async move {
+        .open("database", 1, async move |evt| {
             let db = evt.database();
             let store = db.build_object_store("store").auto_increment().create()?;
 
@@ -48,7 +48,7 @@ async fn example() -> anyhow::Result<()> {
     // In a transaction, add two records
     db.transaction(&["store"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let store = t.object_store("store")?;
             store.add(&JsString::from("bar")).await?;
             store.add(&JsString::from("baz")).await?;
@@ -58,7 +58,7 @@ async fn example() -> anyhow::Result<()> {
 
     // In another transaction, read the first record
     db.transaction(&["store"])
-        .run(|t| async move {
+        .run(async move |t| {
             let data = t.object_store("store")?.get_all(Some(1)).await?;
             if data.len() != 1 {
                 Err(std::io::Error::new(
@@ -73,7 +73,7 @@ async fn example() -> anyhow::Result<()> {
     // If we return `Err` (or panic) from a transaction, then it will abort
     db.transaction(&["store"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let store = t.object_store("store")?;
             store.add(&JsString::from("quux")).await?;
             if store.count().await? > 3 {
@@ -90,7 +90,7 @@ async fn example() -> anyhow::Result<()> {
 
     // And no write will have happened
     db.transaction(&["store"])
-        .run(|t| async move {
+        .run(async move |t| {
             let num_items = t.object_store("store")?.count().await?;
             assert_eq!(num_items, 3);
             Ok(())
@@ -99,7 +99,7 @@ async fn example() -> anyhow::Result<()> {
 
     // More complex example: using cursors to iterate over a store
     db.transaction(&["store"])
-        .run(|t| async move {
+        .run(async move |t| {
             let mut all_items = Vec::new();
             let mut cursor = t.object_store("store")?.cursor().open().await?;
             while let Some(value) = cursor.value() {
diff --git a/examples/basic.rs b/examples/basic.rs
index 86142a3..928775b 100644
--- a/examples/basic.rs
+++ b/examples/basic.rs
@@ -10,7 +10,7 @@ async fn example() -> anyhow::Result<()> {
 
     // Open the database, creating it if needed
     let db = factory
-        .open("database", 1, |evt| async move {
+        .open("database", 1, async move |evt| {
             let db = evt.database();
             let store = db.build_object_store("store").auto_increment().create()?;
 
@@ -25,7 +25,7 @@ async fn example() -> anyhow::Result<()> {
     // In a transaction, add two records
     db.transaction(&["store"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let store = t.object_store("store")?;
             store.add(&JsString::from("bar")).await?;
             store.add(&JsString::from("baz")).await?;
@@ -35,7 +35,7 @@ async fn example() -> anyhow::Result<()> {
 
     // In another transaction, read the first record
     db.transaction(&["store"])
-        .run(|t| async move {
+        .run(async move |t| {
             let data = t.object_store("store")?.get_all(Some(1)).await?;
             if data.len() != 1 {
                 Err(std::io::Error::new(
@@ -50,7 +50,7 @@ async fn example() -> anyhow::Result<()> {
     // If we return `Err` (or panic) from a transaction, then it will abort
     db.transaction(&["store"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let store = t.object_store("store")?;
             store.add(&JsString::from("quux")).await?;
             if store.count().await? > 3 {
@@ -67,7 +67,7 @@ async fn example() -> anyhow::Result<()> {
 
     // And no write will have happened
     db.transaction(&["store"])
-        .run(|t| async move {
+        .run(async move |t| {
             let num_items = t.object_store("store")?.count().await?;
             assert_eq!(num_items, 3);
             Ok(())
@@ -76,7 +76,7 @@ async fn example() -> anyhow::Result<()> {
 
     // More complex example: using cursors to iterate over a store
     db.transaction(&["store"])
-        .run(|t| async move {
+        .run(async move |t| {
             let mut all_items = Vec::new();
             let mut cursor = t.object_store("store")?.cursor().open().await?;
             while let Some(value) = cursor.value() {
diff --git a/src/factory.rs b/src/factory.rs
index b5f55fc..cfcbe73 100644
--- a/src/factory.rs
+++ b/src/factory.rs
@@ -4,7 +4,7 @@ use futures_util::{
     future::{self, Either},
     pin_mut, FutureExt,
 };
-use std::{future::Future, marker::PhantomData};
+use std::marker::PhantomData;
 use web_sys::{
     js_sys::{self, Function},
     wasm_bindgen::{closure::Closure, JsCast, JsValue},
@@ -97,16 +97,12 @@ impl<Err: 'static> Factory<Err> {
     ///
     /// This internally uses [`IDBFactory::open`](https://developer.mozilla.org/en-US/docs/Web/API/IDBFactory/open)
     /// as well as the methods from [`IDBOpenDBRequest`](https://developer.mozilla.org/en-US/docs/Web/API/IDBOpenDBRequest)
-    pub async fn open<Fun, RetFut>(
+    pub async fn open(
         &self,
         name: &str,
         version: u32,
-        on_upgrade_needed: Fun,
-    ) -> crate::Result<Database<Err>, Err>
-    where
-        Fun: 'static + FnOnce(VersionChangeEvent<Err>) -> RetFut,
-        RetFut: 'static + Future<Output = crate::Result<(), Err>>,
-    {
+        on_upgrade_needed: impl 'static + AsyncFnOnce(VersionChangeEvent<Err>) -> crate::Result<(), Err>,
+    ) -> crate::Result<Database<Err>, Err> {
         if version == 0 {
             return Err(crate::Error::VersionMustNotBeZero);
         }
@@ -117,7 +113,7 @@ impl<Err: 'static> Factory<Err> {
             .map_err(crate::Error::from_js_value)?;
 
         let (upgrade_tx, upgrade_rx) = oneshot::channel();
-        let on_upgrade_needed = Closure::once(|evt: IdbVersionChangeEvent| {
+        let on_upgrade_needed = Closure::once(move |evt: IdbVersionChangeEvent| {
             let evt = VersionChangeEvent::from_sys(evt);
             let transaction = evt.transaction().as_sys().clone();
             let fut = {
diff --git a/src/transaction.rs b/src/transaction.rs
index 4780997..5a43bcd 100644
--- a/src/transaction.rs
+++ b/src/transaction.rs
@@ -4,7 +4,7 @@ use crate::{
 };
 use futures_channel::oneshot;
 use futures_util::future::{self, Either};
-use std::{future::Future, marker::PhantomData};
+use std::marker::PhantomData;
 use web_sys::{
     wasm_bindgen::{JsCast, JsValue},
     IdbDatabase, IdbRequest, IdbTransaction, IdbTransactionMode,
@@ -98,10 +98,11 @@ impl<Err> TransactionBuilder<Err> {
     // - If the `Closure` from `transaction_request` has already been dropped, then the callback
     //   will panic. Most likely this will lead to the transaction aborting, but this is an
     //   untested and unsupported code path.
-    pub async fn run<Fun, RetFut, Ret>(self, transaction: Fun) -> crate::Result<Ret, Err>
+    pub async fn run<Ret>(
+        self,
+        transaction: impl 'static + AsyncFnOnce(Transaction<Err>) -> crate::Result<Ret, Err>,
+    ) -> crate::Result<Ret, Err>
     where
-        Fun: 'static + FnOnce(Transaction<Err>) -> RetFut,
-        RetFut: 'static + Future<Output = crate::Result<Ret, Err>>,
         Ret: 'static,
         Err: 'static,
     {
diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index bce5646..2cc7fd6 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -30,15 +30,12 @@ async fn smoke_test() {
 
     // Factory::open
     factory
-        .open("foo", 0, |_| async move { Ok(()) })
+        .open("foo", 0, async move |_| Ok(()))
         .await
         .unwrap_err();
+    factory.open("foo", 2, async move |_| Ok(())).await.unwrap();
     factory
-        .open("foo", 2, |_| async move { Ok(()) })
-        .await
-        .unwrap();
-    factory
-        .open("foo", 1, |_| async move { Ok(()) })
+        .open("foo", 1, async move |_| Ok(()))
         .await
         .unwrap_err();
 
@@ -49,7 +46,7 @@ async fn smoke_test() {
 
     // Database::build_object_store
     let db = factory
-        .open("bar", 1, |evt| async move {
+        .open("bar", 1, async move |evt| {
             let db = evt.database();
             db.build_object_store("objects").create()?;
             db.build_object_store("things")
@@ -67,7 +64,7 @@ async fn smoke_test() {
     db.close();
 
     let db = factory
-        .open("bar", 2, |evt| async move {
+        .open("bar", 2, async move |evt| {
             let db = evt.database();
             db.delete_object_store("things")?;
             Ok(())
@@ -81,7 +78,7 @@ async fn smoke_test() {
     // Transaction
     db.transaction(&["objects", "stuffs"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let objects = t.object_store("objects")?;
             let stuffs = t.object_store("stuffs")?;
 
@@ -105,7 +102,7 @@ async fn smoke_test() {
         .unwrap();
     db.transaction(&["objects", "stuffs"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let objects = t.object_store("objects")?;
             let stuffs = t.object_store("stuffs")?;
 
@@ -135,7 +132,7 @@ async fn smoke_test() {
         .unwrap();
     db.transaction(&["objects"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let objects = t.object_store("objects")?;
 
             // Get
@@ -171,7 +168,7 @@ async fn smoke_test() {
         .unwrap();
     db.transaction(&["stuffs"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let stuffs = t.object_store("stuffs")?;
 
             // Index
@@ -227,7 +224,7 @@ async fn auto_rollback() {
     let factory = Factory::get().unwrap();
 
     let db = factory
-        .open("baz", 1, |evt| async move {
+        .open("baz", 1, async move |evt| {
             let db = evt.database();
             db.build_object_store("data").auto_increment().create()?;
             Ok(())
@@ -237,7 +234,7 @@ async fn auto_rollback() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             t.object_store("data")?.add(&JsString::from("foo")).await?;
             t.object_store("data")?.add(&JsString::from("bar")).await?;
             if true {
@@ -251,7 +248,7 @@ async fn auto_rollback() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             t.object_store("data")?.add(&JsString::from("baz")).await?;
             Ok::<_, indexed_db::Error<()>>(())
         })
@@ -260,7 +257,7 @@ async fn auto_rollback() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             assert_eq!(t.object_store("data")?.count().await?, 1);
             Ok::<_, indexed_db::Error<()>>(())
         })
@@ -273,7 +270,7 @@ async fn duplicate_insert_returns_proper_error_and_does_not_abort() {
     let factory = Factory::<()>::get().unwrap();
 
     let db = factory
-        .open("quux", 1, |evt| async move {
+        .open("quux", 1, async move |evt| {
             let db = evt.database();
             db.build_object_store("data").create()?;
             Ok(())
@@ -283,7 +280,7 @@ async fn duplicate_insert_returns_proper_error_and_does_not_abort() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             t.object_store("data")?
                 .add_kv(&JsString::from("key1"), &JsString::from("foo"))
                 .await?;
@@ -294,7 +291,7 @@ async fn duplicate_insert_returns_proper_error_and_does_not_abort() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             assert!(matches!(
                 t.object_store("data")?
                     .add_kv(&JsString::from("key1"), &JsString::from("bar"))
@@ -312,7 +309,7 @@ async fn duplicate_insert_returns_proper_error_and_does_not_abort() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             assert_eq!(
                 t.object_store("data")?.get_all_keys(None).await?,
                 vec![JsValue::from("key1"), JsValue::from("key2")]
@@ -332,7 +329,7 @@ async fn typed_array_keys() {
     let factory = Factory::<()>::get().unwrap();
 
     let db = factory
-        .open("db12", 1, |evt| async move {
+        .open("db12", 1, async move |evt| {
             let db = evt.database();
             db.build_object_store("data").create()?;
             Ok(())
@@ -342,7 +339,7 @@ async fn typed_array_keys() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             let data = t.object_store("data")?;
             data.add_kv(&Uint8Array::from(&b"key1"[..]), &JsString::from("foo"))
                 .await?;
diff --git a/tests/common_panic/mod.rs b/tests/common_panic/mod.rs
index 484b3fb..6f27572 100644
--- a/tests/common_panic/mod.rs
+++ b/tests/common_panic/mod.rs
@@ -17,7 +17,7 @@ async fn other_awaits_panic() {
     let factory = Factory::<anyhow::Error>::get().unwrap();
 
     let db = factory
-        .open("baz", 1, |evt| async move {
+        .open("baz", 1, async move |evt| {
             let db = evt.database();
             db.build_object_store("data").auto_increment().create()?;
             Ok(())
@@ -29,7 +29,7 @@ async fn other_awaits_panic() {
 
     db.transaction(&["data"])
         .rw()
-        .run(|t| async move {
+        .run(async move |t| {
             t.object_store("data")?.add(&JsString::from("foo")).await?;
             rx.await.context("awaiting for something external")?;
             t.object_store("data")?.add(&JsString::from("bar")).await?;
@@ -52,7 +52,7 @@ async fn await_in_versionchange_panics() {
     let (tx, rx) = futures_channel::oneshot::channel();
 
     factory
-        .open("baz", 1, |evt| async move {
+        .open("baz", 1, async move |evt| {
             let db = evt.database();
             db.build_object_store("data").auto_increment().create()?;
             rx.await.context("awaiting for something external")?;