diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4745be522..7237b791b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        php: ["8.0", "8.1", "8.2", "8.3"]
+        php: ["8.0", "8.1", "8.2", "8.3", "8.4"]
         rust: [stable, nightly]
         clang: ["15", "17"]
         phpts: [ts, nts]
diff --git a/build.rs b/build.rs
index bcaabb416..523256497 100644
--- a/build.rs
+++ b/build.rs
@@ -16,7 +16,7 @@ use bindgen::RustTarget;
 use impl_::Provider;
 
 const MIN_PHP_API_VER: u32 = 20200930;
-const MAX_PHP_API_VER: u32 = 20230831;
+const MAX_PHP_API_VER: u32 = 20240924;
 
 pub trait PHPProvider<'a>: Sized {
     /// Create a new PHP provider.
@@ -230,7 +230,11 @@ fn check_php_version(info: &PHPInfo) -> Result<()> {
 
     const PHP_83_API_VER: u32 = 20230831;
 
-    println!("cargo::rustc-check-cfg=cfg(php80, php81, php82, php83, php_zts, php_debug, docs)");
+    const PHP_84_API_VER: u32 = 20240924;
+
+    println!(
+        "cargo::rustc-check-cfg=cfg(php80, php81, php82, php83, php84, php_zts, php_debug, docs)"
+    );
     println!("cargo:rustc-cfg=php80");
 
     if (PHP_81_API_VER..PHP_82_API_VER).contains(&version) {
@@ -245,6 +249,10 @@ fn check_php_version(info: &PHPInfo) -> Result<()> {
         println!("cargo:rustc-cfg=php83");
     }
 
+    if version >= PHP_84_API_VER {
+        println!("cargo:rustc-cfg=php84");
+    }
+
     Ok(())
 }
 
diff --git a/src/builders/function.rs b/src/builders/function.rs
index 60eddcc96..99f74f7e2 100644
--- a/src/builders/function.rs
+++ b/src/builders/function.rs
@@ -55,6 +55,10 @@ impl<'a> FunctionBuilder<'a> {
                 arg_info: ptr::null(),
                 num_args: 0,
                 flags: 0, // TBD?
+                #[cfg(php84)]
+                doc_comment: ptr::null(),
+                #[cfg(php84)]
+                frameless_function_infos: ptr::null(),
             },
             args: vec![],
             n_req: None,
@@ -79,6 +83,10 @@ impl<'a> FunctionBuilder<'a> {
                 arg_info: ptr::null(),
                 num_args: 0,
                 flags: MethodFlags::Abstract.bits(),
+                #[cfg(php84)]
+                doc_comment: ptr::null(),
+                #[cfg(php84)]
+                frameless_function_infos: ptr::null(),
             },
             args: vec![],
             n_req: None,
diff --git a/src/zend/function.rs b/src/zend/function.rs
index 6e6dd1a39..a16ea1e61 100644
--- a/src/zend/function.rs
+++ b/src/zend/function.rs
@@ -38,6 +38,10 @@ impl FunctionEntry {
             arg_info: ptr::null(),
             num_args: 0,
             flags: 0,
+            #[cfg(php84)]
+            doc_comment: ptr::null(),
+            #[cfg(php84)]
+            frameless_function_infos: ptr::null(),
         }
     }
 
diff --git a/src/zend/handlers.rs b/src/zend/handlers.rs
index 7e88a7e05..5c0da7394 100644
--- a/src/zend/handlers.rs
+++ b/src/zend/handlers.rs
@@ -238,9 +238,18 @@ impl ZendObjectHandlers {
                         let mut zv = Zval::new();
                         val.get(self_, &mut zv)?;
 
-                        #[allow(clippy::unnecessary_mut_passed)]
-                        if zend_is_true(&mut zv) == 1 {
-                            return Ok(1);
+                        cfg_if::cfg_if! {
+                            if #[cfg(php84)] {
+                                #[allow(clippy::unnecessary_mut_passed)]
+                                if zend_is_true(&mut zv) == true {
+                                    return Ok(1);
+                                }
+                            } else {
+                                #[allow(clippy::unnecessary_mut_passed)]
+                                if zend_is_true(&mut zv) == 1 {
+                                    return Ok(1);
+                                }
+                            }
                         }
                     }
                 }
diff --git a/windows_build.rs b/windows_build.rs
index bc0e75d89..39dd4ac89 100644
--- a/windows_build.rs
+++ b/windows_build.rs
@@ -163,12 +163,27 @@ impl DevelPack {
     /// Downloads a new PHP development pack, unzips it in the build script
     /// temporary directory.
     fn new(version: &str, is_zts: bool, arch: Arch) -> Result<DevelPack> {
+        // If the PHP version is more than 8.4.1, use VS17 instead of VS16.
+        let version_float = version
+            .split('.')
+            .take(2)
+            .collect::<Vec<_>>()
+            .join(".")
+            .parse::<f32>()
+            .context("Failed to parse PHP version as float")?;
+
+        // PHP builds switched to VS17 in PHP 8.4.1.
+        let visual_studio_version = if version_float >= 8.4f32 {
+            "vs17"
+        } else {
+            "vs16"
+        };
+
         let zip_name = format!(
             "php-devel-pack-{}{}-Win32-{}-{}.zip",
             version,
             if is_zts { "" } else { "-nts" },
-            "vs16", /* TODO(david): At the moment all PHPs supported by ext-php-rs use VS16 so
-                     * this is constant. */
+            visual_studio_version,
             arch
         );
 
@@ -207,8 +222,10 @@ impl DevelPack {
             Ok(devpack_path)
         }
 
+        let is_archive = if version == "8.4.1" { false } else { true };
+
         download(&zip_name, false)
-            .or_else(|_| download(&zip_name, true))
+            .or_else(|_| download(&zip_name, is_archive))
             .map(DevelPack)
     }