diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 7a78450..696f12b 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -23,7 +23,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.70.0 # MSRV
+          - 1.74.0 # MSRV
           - stable
           - nightly
     steps:
diff --git a/vibrato/Cargo.toml b/vibrato/Cargo.toml
index 3cfa0ac..e55c158 100644
--- a/vibrato/Cargo.toml
+++ b/vibrato/Cargo.toml
@@ -3,7 +3,7 @@ name = "vibrato"
 # NOTE(kampersanda): Developers should check compatibility with MODEL_MAGIC in dictionary.rs.
 version = "0.5.1"
 edition = "2021"
-rust-version = "1.70"
+rust-version = "1.74"
 authors = [
     "Shunsuke Kanda <shnsk.knd@gmail.com>",
     "Koichi Akabe <vbkaisetsu@gmail.com>",
diff --git a/vibrato/src/dictionary/connector/raw_connector/scorer.rs b/vibrato/src/dictionary/connector/raw_connector/scorer.rs
index b8ef6f8..17646e8 100644
--- a/vibrato/src/dictionary/connector/raw_connector/scorer.rs
+++ b/vibrato/src/dictionary/connector/raw_connector/scorer.rs
@@ -60,9 +60,7 @@ impl Default for U31x8 {
 
 impl Decode for U31x8 {
     fn decode<D: Decoder>(decoder: &mut D) -> Result<Self, DecodeError> {
-        let (a, b, c, d, e, f, g, h): (U31, U31, U31, U31, U31, U31, U31, U31) =
-            Decode::decode(decoder)?;
-        let data = [a, b, c, d, e, f, g, h];
+        let data: [U31; 8] = Decode::decode(decoder)?;
 
         // Safety
         debug_assert_eq!(std::mem::size_of_val(data.as_slice()), 32);
@@ -480,4 +478,32 @@ mod tests {
 
         assert_eq!(scorer.accumulate_cost(&[], &[]), 0);
     }
+
+    #[cfg(not(target_feature = "avx2"))]
+    #[test]
+    fn u31x8_encode_decode_test() {
+        let data = U31x8([
+            U31::new(0).unwrap(),
+            U31::new(1).unwrap(),
+            U31::new(2).unwrap(),
+            U31::new(3).unwrap(),
+            U31::new(4).unwrap(),
+            U31::new(5).unwrap(),
+            U31::new(6).unwrap(),
+            U31::new(7).unwrap(),
+        ]);
+
+        let slice: &mut [u8] = &mut [0; 32];
+        let config = bincode::config::standard();
+
+        let mut encoder =
+            bincode::enc::EncoderImpl::new(bincode::enc::write::SliceWriter::new(slice), config);
+        data.encode(&mut encoder).unwrap();
+
+        let mut decoder =
+            bincode::de::DecoderImpl::new(bincode::de::read::SliceReader::new(slice), config);
+        let decoded = U31x8::decode(&mut decoder).unwrap();
+
+        assert_eq!(data.0, decoded.0);
+    }
 }