diff --git a/CHANGELOG.md b/CHANGELOG.md
index d812c73..edd792d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Unreleased
 
+# 0.7.0-alpha.17
+- add `XsdBoolean` for `xsd:boolean` serde compatibility
+- add `closed` field for `Question` (range Object | Link | xsd:datetime | xsd:boolean), and related
+  getters and setters
+
 # 0.7.0-alpha.16
 - implement `IntoIterator` for `&OneOrMany<T>` and `&mut OneOrMany<T>`
 - add `check` function for verifying an IRI's authority
diff --git a/Cargo.toml b/Cargo.toml
index 3372e5e..168e2c3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "activitystreams"
 description = "A set of core types and traits for activitystreams data"
-version = "0.7.0-alpha.16"
+version = "0.7.0-alpha.17"
 license = "GPL-3.0"
 authors = ["asonix <asonix@asonix.dog>"]
 repository = "https://git.asonix.dog/Aardwolf/activitystreams"
@@ -13,14 +13,17 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [workspace]
-members = [
-    "activitystreams-ext",
-    "activitystreams-kinds"
-]
+members = ["activitystreams-ext", "activitystreams-kinds"]
 
 [dependencies]
-activitystreams-kinds = { version = "0.2.0", path = "./activitystreams-kinds/", default-features = false, features = ["iri-string"] }
-iri-string = { version = "0.5.0-beta.1", features = ["serde", "serde-std", "std"] }
+activitystreams-kinds = { version = "0.2.0", path = "./activitystreams-kinds/", default-features = false, features = [
+  "iri-string",
+] }
+iri-string = { version = "0.5.0-beta.1", features = [
+  "serde",
+  "serde-std",
+  "std",
+] }
 mime = "0.3"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
diff --git a/src/activity.rs b/src/activity.rs
index 10d2bfb..c6b95ff 100644
--- a/src/activity.rs
+++ b/src/activity.rs
@@ -25,14 +25,16 @@
 use crate::{
     base::{AnyBase, AsBase, Base, Extends},
     checked::CheckError,
+    either::Either,
     markers,
     object::{ApObject, AsObject, Object},
     prelude::BaseExt,
-    primitives::OneOrMany,
+    primitives::{OneOrMany, XsdBoolean, XsdDateTime},
     unparsed::{Unparsed, UnparsedMut, UnparsedMutExt},
 };
 use iri_string::types::IriString;
 use std::convert::TryFrom;
+use time::OffsetDateTime;
 
 pub use activitystreams_kinds::activity as kind;
 
@@ -1418,6 +1420,185 @@ pub trait QuestionExt: AsQuestion {
         self.question_mut().any_of = None;
         self
     }
+
+    /// Fetch the closed field for the current activity
+    ///
+    /// ```rust
+    /// # use activitystreams::activity::Question;
+    /// # let mut question = Question::new();
+    /// #
+    /// use activitystreams::prelude::*;
+    ///
+    /// if let Some(closed) = question.closed() {
+    ///     println!("{:?}", closed);
+    /// }
+    /// ```
+    fn closed(&self) -> Option<Either<&OneOrMany<AnyBase>, Either<OffsetDateTime, bool>>> {
+        self.question_ref().closed.as_ref().map(|either| {
+            either
+                .as_ref()
+                .map(|l| l, |r| r.as_ref().map(|l| *l.as_datetime(), |r| r.0))
+        })
+    }
+
+    /// Set the closed field for the current activity
+    ///
+    /// This overwrites the contents of any_of
+    ///
+    /// ```rust
+    /// # fn main() -> Result<(), anyhow::Error> {
+    /// use activitystreams::prelude::*;
+    /// # use activitystreams::{activity::Question, iri};
+    /// # let mut question = Question::new();
+    ///
+    /// question.set_closed_base(iri!("https://example.com/one"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn set_closed_base<T>(&mut self, closed: T) -> &mut Self
+    where
+        T: Into<AnyBase>,
+    {
+        self.question_mut().closed = Some(Either::Left(OneOrMany::from_one(closed.into())));
+        self
+    }
+
+    /// Set many closed items for the current activity
+    ///
+    /// This overwrites the contents of any_of
+    ///
+    /// ```rust
+    /// # fn main() -> Result<(), anyhow::Error> {
+    /// use activitystreams::prelude::*;
+    /// # use activitystreams::{activity::Question, iri};
+    /// # let mut question = Question::new();
+    ///
+    /// question.set_many_closed_bases(vec![
+    ///     iri!("https://example.com/one"),
+    ///     iri!("https://example.com/two"),
+    /// ]);
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn set_many_closed_bases<I, T>(&mut self, closed: I) -> &mut Self
+    where
+        I: IntoIterator<Item = T>,
+        T: Into<AnyBase>,
+    {
+        let many = OneOrMany::from_many(closed.into_iter().map(|t| t.into()).collect());
+        self.question_mut().closed = Some(Either::Left(many));
+        self
+    }
+
+    /// Set the closed field as a date
+    ///
+    /// This overwrites the contents of any_of
+    ///
+    /// ```rust
+    /// # fn main() -> Result<(), anyhow::Error> {
+    /// use activitystreams::prelude::*;
+    /// # use activitystreams::{activity::Question, iri};
+    /// # let mut question = Question::new();
+    ///
+    /// question.set_closed_date(time::OffsetDateTime::now_utc());
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn set_closed_date(&mut self, closed: OffsetDateTime) -> &mut Self {
+        self.question_mut().closed = Some(Either::Right(Either::Left(closed.into())));
+        self
+    }
+
+    /// Set the closed field as a boolean
+    ///
+    /// This overwrites the contents of any_of
+    ///
+    /// ```rust
+    /// # fn main() -> Result<(), anyhow::Error> {
+    /// use activitystreams::prelude::*;
+    /// # use activitystreams::{activity::Question, iri};
+    /// # let mut question = Question::new();
+    ///
+    /// question.set_closed_bool(true);
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn set_closed_bool(&mut self, closed: bool) -> &mut Self {
+        self.question_mut().closed = Some(Either::Right(Either::Right(closed.into())));
+        self
+    }
+
+    /// Add an object or link to the closed field
+    ///
+    /// This overwrites the contents of any_of
+    ///
+    /// ```rust
+    /// # fn main() -> Result<(), anyhow::Error> {
+    /// use activitystreams::prelude::*;
+    /// # use activitystreams::{activity::Question, iri};
+    /// # let mut question = Question::new();
+    ///
+    /// question
+    ///     .add_closed_base(iri!("https://example.com/one"))
+    ///     .add_closed_base(iri!("https://example.com/two"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn add_closed_base<T>(&mut self, closed: T) -> &mut Self
+    where
+        T: Into<AnyBase>,
+    {
+        let one_or_many = match self.question_mut().closed.take() {
+            Some(Either::Left(mut one_or_many)) => {
+                one_or_many.add(closed.into());
+                one_or_many
+            }
+            _ => OneOrMany::from_one(closed.into()),
+        };
+
+        self.question_mut().closed = Some(Either::Left(one_or_many));
+        self
+    }
+
+    /// Take the closed field from the current activity
+    ///
+    /// ```rust
+    /// # use activitystreams::activity::Question;
+    /// # let mut question = Question::new();
+    /// #
+    /// use activitystreams::prelude::*;
+    ///
+    /// if let Some(closed) = question.take_closed() {
+    ///     println!("{:?}", closed);
+    /// }
+    /// ```
+    fn take_closed(&mut self) -> Option<Either<OneOrMany<AnyBase>, Either<OffsetDateTime, bool>>> {
+        self.question_mut()
+            .closed
+            .take()
+            .map(|either| either.map(|l| l, |r| r.map(|date| date.into(), |b| b.into())))
+    }
+
+    /// Remove the closed field from the current activity
+    ///
+    /// ```rust
+    /// # fn main() -> Result<(), anyhow::Error> {
+    /// # use activitystreams::{activity::Question, iri};
+    /// # let mut question = Question::new();
+    /// # question.set_closed_bool(true);
+    /// #
+    /// use activitystreams::prelude::*;
+    ///
+    /// assert!(question.closed().is_some());
+    /// question.delete_closed();
+    /// assert!(question.closed().is_none());
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn delete_closed(&mut self) -> &mut Self {
+        self.question_mut().closed = None;
+        self
+    }
 }
 
 /// Indicates that the actor accepts the object.
@@ -1940,6 +2121,13 @@ pub struct Question {
     #[serde(skip_serializing_if = "Option::is_none")]
     any_of: Option<OneOrMany<AnyBase>>,
 
+    /// Indicates that a question has been closed, and answers are no longer accepted.
+    ///
+    /// - Range: Object | Link | xsd:datetime | xsd:boolean
+    /// - Functional: false
+    #[serde(skip_serializing_if = "Option::is_none")]
+    closed: Option<Either<OneOrMany<AnyBase>, Either<XsdDateTime, XsdBoolean>>>,
+
     /// base fields and unparsed json ends up here
     #[serde(flatten)]
     inner: Activity<QuestionType>,
@@ -2619,6 +2807,7 @@ impl Question {
         Question {
             one_of: None,
             any_of: None,
+            closed: None,
             inner: Activity::new(),
         }
     }
@@ -2647,10 +2836,12 @@ impl Question {
 
         let one_of = inner.remove("oneOf")?;
         let any_of = inner.remove("anyOf")?;
+        let closed = inner.remove("closed")?;
 
         Ok(Question {
             one_of,
             any_of,
+            closed,
             inner,
         })
     }
@@ -2659,10 +2850,14 @@ impl Question {
         let Question {
             one_of,
             any_of,
+            closed,
             mut inner,
         } = self;
 
-        inner.insert("oneOf", one_of)?.insert("anyOf", any_of)?;
+        inner
+            .insert("oneOf", one_of)?
+            .insert("anyOf", any_of)?
+            .insert("closed", closed)?;
 
         inner.retracting()
     }
diff --git a/src/primitives/mod.rs b/src/primitives/mod.rs
index c1c53f6..33e2b3d 100644
--- a/src/primitives/mod.rs
+++ b/src/primitives/mod.rs
@@ -18,6 +18,7 @@ mod one_or_many;
 mod rdf_lang_string;
 mod serde_parse;
 mod unit;
+mod xsd_boolean;
 mod xsd_datetime;
 mod xsd_duration;
 
@@ -26,6 +27,7 @@ pub use self::{
     one_or_many::OneOrMany,
     rdf_lang_string::RdfLangString,
     unit::Unit,
+    xsd_boolean::XsdBoolean,
     xsd_datetime::XsdDateTime,
     xsd_duration::{XsdDuration, XsdDurationError},
 };
diff --git a/src/primitives/xsd_boolean.rs b/src/primitives/xsd_boolean.rs
new file mode 100644
index 0000000..78cffad
--- /dev/null
+++ b/src/primitives/xsd_boolean.rs
@@ -0,0 +1,169 @@
+use crate::either::Either;
+use serde::{Deserialize, Serialize};
+use std::ops::{Deref, DerefMut};
+
+/// The type xsd:boolean represents logical yes/no values. The valid values for xsd:boolean are
+/// true, false, 0, and 1. Values that are capitalized (e.g. TRUE) or abbreviated (e.g. T) are not
+/// valid.
+#[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct XsdBoolean(pub bool);
+
+impl XsdBoolean {
+    /// Construct a new XsdBoolean
+    pub fn new(b: bool) -> Self {
+        Self(b)
+    }
+
+    /// Retreive the inner bool
+    pub fn into_inner(self) -> bool {
+        self.0
+    }
+}
+
+impl PartialEq<bool> for XsdBoolean {
+    fn eq(&self, other: &bool) -> bool {
+        self.0 == *other
+    }
+}
+
+impl PartialEq<XsdBoolean> for bool {
+    fn eq(&self, other: &XsdBoolean) -> bool {
+        *self == other.0
+    }
+}
+
+impl Deref for XsdBoolean {
+    type Target = bool;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for XsdBoolean {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl AsRef<bool> for XsdBoolean {
+    fn as_ref(&self) -> &bool {
+        &self.0
+    }
+}
+
+impl AsMut<bool> for XsdBoolean {
+    fn as_mut(&mut self) -> &mut bool {
+        &mut self.0
+    }
+}
+
+impl From<bool> for XsdBoolean {
+    fn from(b: bool) -> Self {
+        Self(b)
+    }
+}
+
+impl From<XsdBoolean> for bool {
+    fn from(b: XsdBoolean) -> Self {
+        b.0
+    }
+}
+
+impl<'de> Deserialize<'de> for XsdBoolean {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let helper: Either<u8, bool> = Deserialize::<'de>::deserialize(deserializer)?;
+
+        match helper {
+            Either::Left(u @ 0 | u @ 1) => Ok(XsdBoolean(u == 1)),
+            Either::Right(b) => Ok(XsdBoolean(b)),
+            _ => Err(serde::de::Error::custom("Invalid boolean")),
+        }
+    }
+}
+
+impl Serialize for XsdBoolean {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.0.serialize(serializer)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::XsdBoolean;
+
+    #[derive(Debug, PartialEq, Eq, serde::Deserialize, serde::Serialize)]
+    struct MyStruct {
+        field: XsdBoolean,
+    }
+
+    #[test]
+    fn deserialize_bool() {
+        let json = r#"[{"field":true},{"field":false}]"#;
+
+        let structs: Vec<MyStruct> = serde_json::from_str(json).unwrap();
+
+        assert_eq!(structs[0].field, true);
+        assert_eq!(structs[1].field, false);
+    }
+
+    #[test]
+    fn deserialize_number() {
+        let json = r#"[{"field":1},{"field":0}]"#;
+
+        let structs: Vec<MyStruct> = serde_json::from_str(json).unwrap();
+
+        assert_eq!(structs[0].field, true);
+        assert_eq!(structs[1].field, false);
+    }
+
+    #[test]
+    fn dont_deserialize_invalid_number() {
+        let invalids = [
+            r#"{"field":2}"#,
+            r#"{"field":3}"#,
+            r#"{"field":4}"#,
+            r#"{"field":-1}"#,
+        ];
+
+        for case in invalids {
+            assert!(serde_json::from_str::<MyStruct>(case).is_err());
+        }
+    }
+
+    #[test]
+    fn dont_deserialize_strings() {
+        let invalids = [
+            r#"{"field":"1"}"#,
+            r#"{"field":"0"}"#,
+            r#"{"field":"true"}"#,
+            r#"{"field":"false"}"#,
+        ];
+
+        for case in invalids {
+            assert!(serde_json::from_str::<MyStruct>(case).is_err());
+        }
+    }
+
+    #[test]
+    fn round_trip() {
+        let structs = vec![
+            MyStruct {
+                field: XsdBoolean(false),
+            },
+            MyStruct {
+                field: XsdBoolean(true),
+            },
+        ];
+        let string = serde_json::to_string(&structs).unwrap();
+        let new_structs: Vec<MyStruct> = serde_json::from_str(&string).unwrap();
+
+        assert_eq!(structs, new_structs);
+    }
+}