diff --git a/README.md b/README.md
index bb72e4b49..00412109f 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ Select a version of `kube` along with the generated [k8s-openapi](https://github
 [dependencies]
 kube = "0.56.0"
 kube-runtime = "0.56.0"
-k8s-openapi = { version = "0.11.0", default-features = false, features = ["v1_20"] }
+k8s-openapi = { version = "0.12.0", default-features = false, features = ["v1_20"] }
 ```
 
 [Features are available](https://github.com/clux/kube-rs/blob/master/kube/Cargo.toml#L18).
@@ -159,7 +159,7 @@ Kube has basic support ([with caveats](https://github.com/clux/kube-rs/issues?q=
 [dependencies]
 kube = { version = "0.56.0", default-features = false, features = ["client", "rustls-tls"] }
 kube-runtime = { version = "0.56.0" }
-k8s-openapi = { version = "0.11.0", default-features = false, features = ["v1_20"] }
+k8s-openapi = { version = "0.12.0", default-features = false, features = ["v1_20"] }
 ```
 
 This will pull in `rustls` and `hyper-rustls`.
diff --git a/examples/Cargo.toml b/examples/Cargo.toml
index f45272333..10622bf17 100644
--- a/examples/Cargo.toml
+++ b/examples/Cargo.toml
@@ -31,7 +31,7 @@ kube = { path = "../kube", version = "^0.56.0", default-features = false, featur
 kube-derive = { path = "../kube-derive", version = "^0.56.0", default-features = false } # only needed to opt out of schema
 kube-runtime = { path = "../kube-runtime", version = "^0.56.0"}
 kube-core = { path = "../kube-core", version = "^0.56.0", default-features = false }
-k8s-openapi = { version = "0.11.0", features = ["v1_20"], default-features = false }
+k8s-openapi = { version = "0.12.0", features = ["v1_20"], default-features = false }
 log = "0.4.11"
 serde = { version = "1.0.118", features = ["derive"] }
 serde_json = "1.0.61"
diff --git a/examples/configmapgen_controller.rs b/examples/configmapgen_controller.rs
index c70e9ee49..48f3e7e3a 100644
--- a/examples/configmapgen_controller.rs
+++ b/examples/configmapgen_controller.rs
@@ -61,13 +61,13 @@ async fn reconcile(generator: ConfigMapGenerator, ctx: Context<Data>) -> Result<
     let cm = ConfigMap {
         metadata: ObjectMeta {
             name: generator.metadata.name.clone(),
-            owner_references: Some(vec![OwnerReference {
+            owner_references: vec![OwnerReference {
                 controller: Some(true),
                 ..object_to_owner_reference::<ConfigMapGenerator>(generator.metadata.clone())?
-            }]),
+            }],
             ..ObjectMeta::default()
         },
-        data: Some(contents),
+        data: contents,
         ..Default::default()
     };
     let cm_api = Api::<ConfigMap>::namespaced(
diff --git a/examples/crd_api.rs b/examples/crd_api.rs
index b22ea4803..2fd93ce2d 100644
--- a/examples/crd_api.rs
+++ b/examples/crd_api.rs
@@ -52,7 +52,7 @@ async fn main() -> anyhow::Result<()> {
             info!(
                 "Deleting {}: ({:?})",
                 o.name(),
-                o.status.unwrap().conditions.unwrap().last()
+                o.status.unwrap().conditions.last()
             );
         })
         .map_right(|s| {
@@ -213,7 +213,7 @@ async fn main() -> anyhow::Result<()> {
             info!(
                 "Deleting {} CRD definition: {:?}",
                 o.name(),
-                o.status.unwrap().conditions.unwrap().last()
+                o.status.unwrap().conditions.last()
             );
         }
         Right(status) => {
diff --git a/examples/crd_apply.rs b/examples/crd_apply.rs
index f76c0ca59..0b0f66a56 100644
--- a/examples/crd_apply.rs
+++ b/examples/crd_apply.rs
@@ -92,12 +92,10 @@ async fn wait_for_crd_ready(crds: &Api<CustomResourceDefinition>) -> anyhow::Res
         if let WatchEvent::Modified(s) = status {
             info!("Modify event for {}", s.name());
             if let Some(s) = s.status {
-                if let Some(conds) = s.conditions {
-                    if let Some(pcond) = conds.iter().find(|c| c.type_ == "NamesAccepted") {
-                        if pcond.status == "True" {
-                            info!("crd was accepted: {:?}", pcond);
-                            return Ok(());
-                        }
+                if let Some(pcond) = s.conditions.iter().find(|c| c.type_ == "NamesAccepted") {
+                    if pcond.status == "True" {
+                        info!("crd was accepted: {:?}", pcond);
+                        return Ok(());
                     }
                 }
             }
diff --git a/examples/crd_derive_schema.rs b/examples/crd_derive_schema.rs
index 1dc328f75..4088c382d 100644
--- a/examples/crd_derive_schema.rs
+++ b/examples/crd_derive_schema.rs
@@ -235,9 +235,9 @@ async fn create_crd(client: Client) -> Result<CustomResourceDefinition> {
             let accepted = crd
                 .status
                 .as_ref()
-                .and_then(|s| s.conditions.as_ref())
-                .map(|cs| {
-                    cs.iter()
+                .map(|s| {
+                    s.conditions
+                        .iter()
                         .any(|c| c.type_ == "NamesAccepted" && c.status == "True")
                 })
                 .unwrap_or(false);
diff --git a/examples/node_watcher.rs b/examples/node_watcher.rs
index f3a5fabad..6bb22a8cc 100644
--- a/examples/node_watcher.rs
+++ b/examples/node_watcher.rs
@@ -33,7 +33,6 @@ async fn check_for_node_failures(events: &Api<Event>, o: Node) -> anyhow::Result
             .status
             .unwrap()
             .conditions
-            .unwrap()
             .into_iter()
             .filter(|c| {
                 // In a failed state either some of the extra conditions are not False
diff --git a/examples/pod_watcher.rs b/examples/pod_watcher.rs
index c8c011a41..320f79b11 100644
--- a/examples/pod_watcher.rs
+++ b/examples/pod_watcher.rs
@@ -29,19 +29,18 @@ async fn main() -> Result<()> {
 
 fn pod_unready(p: &Pod) -> Option<String> {
     let status = p.status.as_ref().unwrap();
-    if let Some(conds) = &status.conditions {
-        let failed = conds
-            .into_iter()
-            .filter(|c| c.type_ == "Ready" && c.status == "False")
-            .map(|c| c.message.clone().unwrap_or_default())
-            .collect::<Vec<_>>()
-            .join(",");
-        if !failed.is_empty() {
-            if p.metadata.labels.as_ref().unwrap().contains_key("job-name") {
-                return None; // ignore job based pods, they are meant to exit 0
-            }
-            return Some(format!("Unready pod {}: {}", p.name(), failed));
+    let failed = status
+        .conditions
+        .iter()
+        .filter(|c| c.type_ == "Ready" && c.status == "False")
+        .map(|c| c.message.clone().unwrap_or_default())
+        .collect::<Vec<_>>()
+        .join(",");
+    if !failed.is_empty() {
+        if p.metadata.labels.contains_key("job-name") {
+            return None; // ignore job based pods, they are meant to exit 0
         }
+        return Some(format!("Unready pod {}: {}", p.name(), failed));
     }
     None
 }
diff --git a/examples/secret_reflector.rs b/examples/secret_reflector.rs
index bbedff9a4..068099472 100644
--- a/examples/secret_reflector.rs
+++ b/examples/secret_reflector.rs
@@ -20,13 +20,12 @@ enum Decoded {
 fn decode(secret: &Secret) -> BTreeMap<String, Decoded> {
     let mut res = BTreeMap::new();
     // Ignoring binary data for now
-    if let Some(data) = secret.data.clone() {
-        for (k, v) in data {
-            if let Ok(b) = std::str::from_utf8(&v.0) {
-                res.insert(k, Decoded::Utf8(b.to_string()));
-            } else {
-                res.insert(k, Decoded::Bytes(v.0));
-            }
+    let data = secret.data.clone();
+    for (k, v) in data {
+        if let Ok(b) = std::str::from_utf8(&v.0) {
+            res.insert(k, Decoded::Utf8(b.to_string()));
+        } else {
+            res.insert(k, Decoded::Bytes(v.0));
         }
     }
     res
diff --git a/kube-core/Cargo.toml b/kube-core/Cargo.toml
index 991bbdbe3..9125b0b8a 100644
--- a/kube-core/Cargo.toml
+++ b/kube-core/Cargo.toml
@@ -20,18 +20,17 @@ jsonpatch = ["json-patch"]
 serde = { version = "1.0.118", features = ["derive"] }
 serde_json = "1.0.61"
 thiserror = "1.0.23"
-once_cell = "1.7.2"
 form_urlencoded = "1.0.1"
 http = "0.2.2"
 json-patch = { version = "0.2.6", optional = true }
 
 [dependencies.k8s-openapi]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 features = []
 
 [dev-dependencies.k8s-openapi]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 features = ["v1_20"]
 
diff --git a/kube-core/src/params.rs b/kube-core/src/params.rs
index 191bde16b..b3c9b596a 100644
--- a/kube-core/src/params.rs
+++ b/kube-core/src/params.rs
@@ -192,7 +192,7 @@ impl PostParams {
 /// use k8s_openapi::apimachinery::pkg::apis::meta::v1::ObjectMeta;
 /// let r = Role {
 ///     metadata: ObjectMeta { name: Some("user".into()), ..ObjectMeta::default() },
-///     rules: Some(vec![])
+///     rules: vec![]
 /// };
 /// let patch = Patch::Apply(&r);
 /// ```
diff --git a/kube-core/src/resource.rs b/kube-core/src/resource.rs
index 77c7a53c1..a60777aae 100644
--- a/kube-core/src/resource.rs
+++ b/kube-core/src/resource.rs
@@ -1,6 +1,5 @@
 pub use k8s_openapi::apimachinery::pkg::apis::meta::v1::ObjectMeta;
 use k8s_openapi::apimachinery::pkg::apis::meta::v1::OwnerReference;
-use once_cell::sync::Lazy;
 use std::{borrow::Cow, collections::BTreeMap};
 
 /// An accessor trait for a kubernetes Resource.
@@ -148,10 +147,6 @@ pub trait ResourceExt: Resource {
     fn finalizers_mut(&mut self) -> &mut Vec<String>;
 }
 
-// TODO: replace with ordinary static when BTreeMap::new() is no longer
-// const-unstable.
-static EMPTY_MAP: Lazy<BTreeMap<String, String>> = Lazy::new(BTreeMap::new);
-
 impl<K: Resource> ResourceExt for K {
     fn name(&self) -> String {
         self.meta().name.clone().expect(".metadata.name missing")
@@ -170,35 +165,35 @@ impl<K: Resource> ResourceExt for K {
     }
 
     fn labels(&self) -> &BTreeMap<String, String> {
-        self.meta().labels.as_ref().unwrap_or_else(|| &*EMPTY_MAP)
+        &self.meta().labels
     }
 
     fn labels_mut(&mut self) -> &mut BTreeMap<String, String> {
-        self.meta_mut().labels.get_or_insert_with(BTreeMap::new)
+        &mut self.meta_mut().labels
     }
 
     fn annotations(&self) -> &BTreeMap<String, String> {
-        self.meta().annotations.as_ref().unwrap_or_else(|| &*EMPTY_MAP)
+        &self.meta().annotations
     }
 
     fn annotations_mut(&mut self) -> &mut BTreeMap<String, String> {
-        self.meta_mut().annotations.get_or_insert_with(BTreeMap::new)
+        &mut self.meta_mut().annotations
     }
 
     fn owner_references(&self) -> &[OwnerReference] {
-        self.meta().owner_references.as_deref().unwrap_or_default()
+        self.meta().owner_references.as_slice()
     }
 
     fn owner_references_mut(&mut self) -> &mut Vec<OwnerReference> {
-        self.meta_mut().owner_references.get_or_insert_with(Vec::new)
+        &mut self.meta_mut().owner_references
     }
 
     fn finalizers(&self) -> &[String] {
-        self.meta().finalizers.as_deref().unwrap_or_default()
+        self.meta().finalizers.as_slice()
     }
 
     fn finalizers_mut(&mut self) -> &mut Vec<String> {
-        self.meta_mut().finalizers.get_or_insert_with(Vec::new)
+        &mut self.meta_mut().finalizers
     }
 }
 
diff --git a/kube-derive/Cargo.toml b/kube-derive/Cargo.toml
index ffd1cd107..2d411f745 100644
--- a/kube-derive/Cargo.toml
+++ b/kube-derive/Cargo.toml
@@ -29,7 +29,7 @@ schema = []
 serde = { version = "1.0.118", features = ["derive"] }
 serde_yaml = "0.8.17"
 kube = { path = "../kube", default-features = false }
-k8s-openapi = { version = "0.11.0", default-features = false, features = ["v1_20"] }
+k8s-openapi = { version = "0.12.0", default-features = false, features = ["v1_20"] }
 schemars = { version = "0.8.0", features = ["chrono"] }
 chrono = "0.4.19"
 trybuild = "1.0"
diff --git a/kube-runtime/Cargo.toml b/kube-runtime/Cargo.toml
index 4a646ca32..9e65172a5 100644
--- a/kube-runtime/Cargo.toml
+++ b/kube-runtime/Cargo.toml
@@ -25,7 +25,7 @@ dashmap = "4.0.1"
 tokio-util = { version = "0.6.0", features = ["time"] }
 
 [dependencies.k8s-openapi]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 
 [dev-dependencies]
@@ -37,6 +37,6 @@ rand = "0.8.0"
 schemars = "0.8.0"
 
 [dev-dependencies.k8s-openapi]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 features = ["v1_20"]
diff --git a/kube-runtime/src/controller/mod.rs b/kube-runtime/src/controller/mod.rs
index 2b5c150af..50521115a 100644
--- a/kube-runtime/src/controller/mod.rs
+++ b/kube-runtime/src/controller/mod.rs
@@ -104,7 +104,6 @@ where
         let dt = owner_type.clone();
         meta.owner_references
             .into_iter()
-            .flatten()
             .flat_map(move |owner| ObjectRef::from_owner_ref(ns.as_deref(), &owner, dt.clone()))
     })
 }
diff --git a/kube-runtime/src/reflector/mod.rs b/kube-runtime/src/reflector/mod.rs
index 12bf7497c..6051cbaa7 100644
--- a/kube-runtime/src/reflector/mod.rs
+++ b/kube-runtime/src/reflector/mod.rs
@@ -70,11 +70,11 @@ mod tests {
             ..ConfigMap::default()
         };
         let updated_cm = ConfigMap {
-            data: Some({
+            data: {
                 let mut data = BTreeMap::new();
                 data.insert("data".to_string(), "present!".to_string());
                 data
-            }),
+            },
             ..cm.clone()
         };
         reflector(
diff --git a/kube/Cargo.toml b/kube/Cargo.toml
index e94a6d1a0..a3668bc34 100644
--- a/kube/Cargo.toml
+++ b/kube/Cargo.toml
@@ -73,7 +73,7 @@ rand = { version = "0.8.3", optional = true }
 tracing = { version = "0.1.25", features = ["log"], optional = true }
 
 [dependencies.k8s-openapi]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 features = []
 
@@ -85,6 +85,6 @@ tokio-test = "0.4.0"
 tower-test = "0.4.0"
 
 [dev-dependencies.k8s-openapi]
-version = "0.11.0"
+version = "0.12.0"
 default-features = false
 features = ["v1_20"]
diff --git a/kube/src/client/mod.rs b/kube/src/client/mod.rs
index 2fe65370e..f655529b4 100644
--- a/kube/src/client/mod.rs
+++ b/kube/src/client/mod.rs
@@ -606,7 +606,7 @@ mod tests {
 
         let pods: Api<Pod> = Api::default_namespaced(Client::new(mock_service, "default"));
         let pod = pods.get("test").await.unwrap();
-        assert_eq!(pod.metadata.annotations.unwrap().get("kube-rs").unwrap(), "test");
+        assert_eq!(pod.metadata.annotations.get("kube-rs").unwrap(), "test");
         spawned.await.unwrap();
     }
 }
diff --git a/tests/Cargo.toml b/tests/Cargo.toml
index a9723ee45..dde2235e4 100644
--- a/tests/Cargo.toml
+++ b/tests/Cargo.toml
@@ -17,7 +17,7 @@ anyhow = "1.0.37"
 env_logger = "0.8.2"
 futures = "0.3.8"
 kube = { path = "../kube", version = "^0.56.0"}
-k8s-openapi = { version = "0.11.0", features = ["v1_20"], default-features = false }
+k8s-openapi = { version = "0.12.0", features = ["v1_20"], default-features = false }
 log = "0.4.11"
 serde_json = "1.0.61"
 tokio = { version = "1.0.1", features = ["full"] }