diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index a671fa6..bc5d1d6 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,2 +1,2 @@
 [toolchain]
-channel = "nightly-2024-05-07"
+channel = "nightly-2024-08-01"
diff --git a/src/cs/implementations/fast_serialization.rs b/src/cs/implementations/fast_serialization.rs
index ea7301c..7288270 100644
--- a/src/cs/implementations/fast_serialization.rs
+++ b/src/cs/implementations/fast_serialization.rs
@@ -272,7 +272,7 @@ where
 {
     fn write_into_buffer<W: Write>(&self, mut dst: W) -> Result<(), Box<dyn Error>> {
         // we avoid transmute here
-        let flattened_self = self[..].flatten();
+        let flattened_self = self[..].as_flattened();
 
         let len_as_base = flattened_self.len();
         let len_le_bytes = (len_as_base as u64).to_le_bytes();
@@ -346,7 +346,7 @@ where
 {
     fn write_into_buffer<W: Write>(&self, mut dst: W) -> Result<(), Box<dyn Error>> {
         // we avoid transmute here
-        let flattened_self = self[..].flatten();
+        let flattened_self = self[..].as_flattened();
 
         let len_as_base = flattened_self.len();
         let len_le_bytes = (len_as_base as u64).to_le_bytes();
diff --git a/src/lib.rs b/src/lib.rs
index 8eb9e9f..6978fa7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -53,7 +53,6 @@
 #![feature(vec_push_within_capacity)]
 #![feature(return_position_impl_trait_in_trait)]
 #![feature(type_changing_struct_update)]
-#![feature(slice_flatten)]
 #![cfg_attr(feature = "include_packed_simd", feature(stdsimd))]
 
 pub mod algebraic_props;