diff --git a/Cargo.lock b/Cargo.lock
index 7f30e0f..6b36acf 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -49,9 +49,9 @@ dependencies = [
 name = "econf-derive"
 version = "0.2.1"
 dependencies = [
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "syn 0.15.44",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -130,15 +130,6 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
 
-[[package]]
-name = "proc-macro2"
-version = "0.4.30"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
-dependencies = [
- "unicode-xid",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.86"
@@ -148,22 +139,13 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "quote"
-version = "0.6.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
-dependencies = [
- "proc-macro2 0.4.30",
-]
-
 [[package]]
 name = "quote"
 version = "1.0.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fa76aaf39101c457836aec0ce2316dbdc3ab723cdda1c6bd4e6ad4208acaca7"
 dependencies = [
- "proc-macro2 1.0.86",
+ "proc-macro2",
 ]
 
 [[package]]
@@ -187,9 +169,9 @@ version = "1.0.203"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "500cbc0ebeb6f46627f50f3f5811ccf6bf00643be300b4c3eabc0ef55dc5b5ba"
 dependencies = [
- "proc-macro2 1.0.86",
- "quote 1.0.36",
- "syn 2.0.68",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -216,25 +198,14 @@ dependencies = [
  "windows-sys",
 ]
 
-[[package]]
-name = "syn"
-version = "0.15.44"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ca4b3b69a77cbe1ffc9e198781b7acb0c7365a883670e8f1c1bc66fba79a5c5"
-dependencies = [
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "unicode-xid",
-]
-
 [[package]]
 name = "syn"
 version = "2.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "901fa70d88b9d6c98022e23b4136f9f3e54e4662c3bc1bd1d84a42a9a0f0c1e9"
 dependencies = [
- "proc-macro2 1.0.86",
- "quote 1.0.36",
+ "proc-macro2",
+ "quote",
  "unicode-ident",
 ]
 
@@ -277,12 +248,6 @@ version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
 
-[[package]]
-name = "unicode-xid"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
-
 [[package]]
 name = "windows-sys"
 version = "0.48.0"
diff --git a/econf-derive/Cargo.toml b/econf-derive/Cargo.toml
index 2307a88..1f50c68 100644
--- a/econf-derive/Cargo.toml
+++ b/econf-derive/Cargo.toml
@@ -11,9 +11,9 @@ repository = "https://github.com/YushiOMOTE/econf"
 readme = "README.md"
 
 [dependencies]
-syn = "0.15"
-quote = "0.6"
-proc-macro2 = "0.4"
+syn = "2"
+quote = "1"
+proc-macro2 = "1"
 
 [lib]
 proc-macro = true
diff --git a/econf-derive/src/lib.rs b/econf-derive/src/lib.rs
index 4d98f4d..f459f18 100644
--- a/econf-derive/src/lib.rs
+++ b/econf-derive/src/lib.rs
@@ -4,7 +4,7 @@ use proc_macro::TokenStream;
 
 use proc_macro2::{Ident, TokenStream as TokenStream2};
 use quote::quote;
-use syn::{parse_macro_input, Data, DeriveInput, Field, Fields, Lit, Meta, NestedMeta};
+use syn::{parse_macro_input, Data, DeriveInput, Field, Fields, LitStr};
 
 #[proc_macro_derive(LoadEnv, attributes(econf))]
 pub fn load_env(input: TokenStream) -> TokenStream {
@@ -26,31 +26,34 @@ pub fn load_env(input: TokenStream) -> TokenStream {
 }
 
 fn is_skip(f: &Field) -> bool {
-    f.attrs.iter().any(|a| {
-        a.path.is_ident("econf")
-            && matches!(a.parse_meta().unwrap(), Meta::List(meta) if meta.nested.iter().any(|nm| {
-                matches!(nm, NestedMeta::Meta(Meta::Word(word)) if *word == "skip")
-            }))
+    f.attrs.iter().any(|attr| {
+        if attr.path().is_ident("econf") {
+            if let Ok(args) = attr.parse_args::<Ident>() {
+                return args == "skip";
+            }
+        }
+
+        false
     })
 }
 
 fn find_renaming(f: &Field) -> Option<String> {
-    f.attrs
-        .iter()
-        .filter(|attr| attr.path.is_ident("econf"))
-        .filter_map(|attr| match attr.parse_meta().unwrap() {
-            Meta::List(meta) => Some(meta.nested),
-            _ => None,
-        })
-        .flat_map(|nested| nested.into_iter())
-        .filter_map(|nested| match nested {
-            NestedMeta::Meta(Meta::NameValue(value)) if value.ident == "rename" => Some(value),
-            _ => None,
-        })
-        .find_map(|value| match value.lit {
-            Lit::Str(token) => Some(token.value()),
-            _ => None,
-        })
+    let mut rename = None;
+    for attr in &f.attrs {
+        if attr.path().is_ident("econf") {
+            attr.parse_nested_meta(|meta| {
+                if meta.path.is_ident("rename") {
+                    let s: LitStr = meta.value()?.parse()?;
+                    rename = Some(s.value());
+                }
+
+                Ok(())
+            })
+            .expect("failed to parse nested meta");
+        }
+    }
+
+    rename
 }
 
 fn content(name: &Ident, data: &Data) -> TokenStream2 {
diff --git a/econf/Cargo.toml b/econf/Cargo.toml
index fc358b2..7400a38 100644
--- a/econf/Cargo.toml
+++ b/econf/Cargo.toml
@@ -14,7 +14,7 @@ readme = "README.md"
 log = "0.4"
 serde = "1.0"
 serde_yaml = "0.8"
-econf-derive = { version = "0.2.1", path = "../econf-derive" }
+econf-derive = { path = "../econf-derive" }
 humantime = "2.1"
 
 [dev-dependencies]