diff --git a/hugr-cli/Cargo.toml b/hugr-cli/Cargo.toml
index a517d8f48..976bcdb2f 100644
--- a/hugr-cli/Cargo.toml
+++ b/hugr-cli/Cargo.toml
@@ -25,6 +25,13 @@ clio = { workspace = true, features = ["clap-parse"] }
 [lints]
 workspace = true
 
+[package.metadata.cargo-semver-checks.lints]
+workspace = true
+# Temporarily disabled due to Package being moved to `hugr-core` triggering an error in rustdoc
+# https://github.com/obi1kenobi/cargo-semver-checks/issues/355
+enum_missing = "warn"
+struct_missing = "warn"
+
 [dev-dependencies]
 assert_cmd = { workspace = true }
 assert_fs = { workspace = true }
diff --git a/hugr-cli/src/lib.rs b/hugr-cli/src/lib.rs
index 41db94653..24cc40e2b 100644
--- a/hugr-cli/src/lib.rs
+++ b/hugr-cli/src/lib.rs
@@ -14,6 +14,8 @@ pub mod mermaid;
 pub mod validate;
 
 // TODO: Deprecated re-export. Remove on a breaking release.
+#[doc(inline)]
+#[deprecated(since = "0.13.2", note = "Use `hugr::package::Package` instead.")]
 pub use hugr::package::Package;
 
 /// CLI arguments.
@@ -126,4 +128,17 @@ impl HugrArgs {
         let pkg = serde_json::from_value::<Package>(val.clone())?;
         Ok(PackageOrHugr::Package(pkg))
     }
+
+    /// Read either a package from the input.
+    ///
+    /// deprecated: use [HugrArgs::get_package_or_hugr] instead.
+    #[deprecated(
+        since = "0.13.2",
+        note = "Use `HugrArgs::get_package_or_hugr` instead."
+    )]
+    pub fn get_package(&mut self) -> Result<Package, CliError> {
+        let val: serde_json::Value = serde_json::from_reader(&mut self.input)?;
+        let pkg = serde_json::from_value::<Package>(val.clone())?;
+        Ok(pkg)
+    }
 }
diff --git a/hugr-cli/src/validate.rs b/hugr-cli/src/validate.rs
index eaf3bfccd..996799b77 100644
--- a/hugr-cli/src/validate.rs
+++ b/hugr-cli/src/validate.rs
@@ -7,6 +7,14 @@ use hugr::{extension::ExtensionRegistry, Extension, Hugr};
 
 use crate::{CliError, HugrArgs};
 
+// TODO: Deprecated re-export. Remove on a breaking release.
+#[doc(inline)]
+#[deprecated(
+    since = "0.13.2",
+    note = "Use `hugr::package::PackageValidationError` instead."
+)]
+pub use hugr::package::PackageValidationError as ValError;
+
 /// Validate and visualise a HUGR file.
 #[derive(Parser, Debug)]
 #[clap(version = "1.0", long_about = None)]
diff --git a/hugr-core/src/package.rs b/hugr-core/src/package.rs
index 7dd10010b..586d31c3e 100644
--- a/hugr-core/src/package.rs
+++ b/hugr-core/src/package.rs
@@ -106,6 +106,22 @@ impl Package {
         Ok(())
     }
 
+    /// Validate the package against an extension registry.
+    ///
+    /// `reg` is updated with any new extensions.
+    ///
+    /// Returns the validated modules.
+    ///
+    /// deprecated: use [Package::update_validate] instead.
+    #[deprecated(since = "0.13.2", note = "Replaced by `Package::update_validate`")]
+    pub fn validate(
+        mut self,
+        reg: &mut ExtensionRegistry,
+    ) -> Result<Vec<Hugr>, PackageValidationError> {
+        self.update_validate(reg)?;
+        Ok(self.modules)
+    }
+
     /// Read a Package in json format from an io reader.
     ///
     /// If the json encodes a single [Hugr] instead, it will be inserted in a new [Package].
@@ -259,13 +275,57 @@ pub enum PackageEncodingError {
 }
 
 /// Error raised while validating a package.
-#[derive(Debug, Display, Error, From)]
+#[derive(Debug, From)]
 #[non_exhaustive]
 pub enum PackageValidationError {
     /// Error raised while processing the package extensions.
     Extension(ExtensionRegistryError),
     /// Error raised while validating the package hugrs.
     Validation(ValidationError),
+    /// Error validating HUGR.
+    // TODO: Remove manual Display and Error impls when removing deprecated variants.
+    #[from(ignore)]
+    #[deprecated(
+        since = "0.13.2",
+        note = "Replaced by `PackageValidationError::Validation`"
+    )]
+    Validate(ValidationError),
+    /// Error registering extension.
+    // TODO: Remove manual Display and Error impls when removing deprecated variants.
+    #[from(ignore)]
+    #[deprecated(
+        since = "0.13.2",
+        note = "Replaced by `PackageValidationError::Extension`"
+    )]
+    ExtReg(ExtensionRegistryError),
+}
+
+// Note: We cannot use the `derive_more::Error` derive due to a bug with deprecated elements.
+// See https://github.com/JelteF/derive_more/issues/419
+#[allow(deprecated)]
+impl std::error::Error for PackageValidationError {
+    fn source(&self) -> Option<&(dyn derive_more::Error + 'static)> {
+        match self {
+            PackageValidationError::Extension(source) => Some(source),
+            PackageValidationError::Validation(source) => Some(source),
+            PackageValidationError::Validate(source) => Some(source),
+            PackageValidationError::ExtReg(source) => Some(source),
+        }
+    }
+}
+
+// Note: We cannot use the `derive_more::Display` derive due to a bug with deprecated elements.
+// See https://github.com/JelteF/derive_more/issues/419
+impl Display for PackageValidationError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        #[allow(deprecated)]
+        match self {
+            PackageValidationError::Extension(e) => write!(f, "Error processing extensions: {}", e),
+            PackageValidationError::Validation(e) => write!(f, "Error validating HUGR: {}", e),
+            PackageValidationError::Validate(e) => write!(f, "Error validating HUGR: {}", e),
+            PackageValidationError::ExtReg(e) => write!(f, "Error registering extension: {}", e),
+        }
+    }
 }
 
 #[cfg(test)]
diff --git a/release-please-config.json b/release-please-config.json
index 54e6bdf7b..7cbb53196 100644
--- a/release-please-config.json
+++ b/release-please-config.json
@@ -63,4 +63,4 @@
             "hidden": true
         }
     ]
-}
\ No newline at end of file
+}