diff --git a/Cargo.toml b/Cargo.toml
index d43de4210..f3c1aaba2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,12 +22,12 @@ smallvec = { version = "1.7.0", default-features = false, features = ["union", "
 thin-vec = { version = "0.2.13", default-features = false }
 ahash = { version = "0.8.2", default-features = false, features = ["compile-time-rng"] }
 num-traits = { version = "0.2.0", default-features = false }
-once_cell = { version = "1.7.0", default-features = false, features = ["race"] }
+once_cell = { version = "1.19.0", default-features = false, features = ["critical-section"] }
 bitflags = { version = "2.0.0", default-features = false }
 smartstring = { version = "1.0.0", default-features = false }
 rhai_codegen = { version = "2.1.0", path = "codegen" }
 
-no-std-compat = { git = "https://gitlab.com/jD91mZM2/no-std-compat", version = "0.4.1", default-features = false, features = ["alloc", "compat_sync"], optional = true }
+no-std-compat = { git = "https://gitlab.com/jD91mZM2/no-std-compat", version = "0.4.1", default-features = false, features = ["alloc"], optional = true }
 libm = { version = "0.2.0", default-features = false, optional = true }
 hashbrown = { version = "0.14.0", optional = true }
 core-error = { version = "0.0.0", default-features = false, features = ["alloc"], optional = true }
@@ -54,7 +54,7 @@ std = ["once_cell/std", "ahash/std", "num-traits/std", "smartstring/std"]
 #! ### Enable Special Functionalities
 
 ## Require that all data types implement `Send + Sync` (for multi-threaded usage).
-sync = []
+sync = ["no-std-compat/compat_sync"]
 ## Add support for the [`Decimal`](https://crates.io/crates/rust_decimal) data type (acts as the system floating-point type under `no_float`).
 decimal = ["rust_decimal"]
 ## Enable serialization/deserialization of Rhai data types via [`serde`](https://crates.io/crates/serde).
diff --git a/src/config/hashing.rs b/src/config/hashing.rs
index cf7fcda5f..e6dcee9ae 100644
--- a/src/config/hashing.rs
+++ b/src/config/hashing.rs
@@ -54,11 +54,7 @@ pub use crate::api::deprecated::config::hashing::{get_ahash_seed, set_ahash_seed
 /// ```
 #[inline(always)]
 pub fn set_hashing_seed(new_seed: Option<[u64; 4]>) -> Result<(), Option<[u64; 4]>> {
-    #[cfg(feature = "std")]
-    return HASHING_SEED.set(new_seed);
-
-    #[cfg(not(feature = "std"))]
-    return HASHING_SEED.set(new_seed.into()).map_err(|err| *err);
+    HASHING_SEED.set(new_seed)
 }
 
 /// Get the current hashing Seed.
diff --git a/src/lib.rs b/src/lib.rs
index 525df595c..d351a60d5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -220,12 +220,8 @@ type ExclusiveRange = std::ops::Range<INT>;
 /// An inclusive integer range.
 type InclusiveRange = std::ops::RangeInclusive<INT>;
 
-#[cfg(feature = "std")]
 use once_cell::sync::OnceCell;
 
-#[cfg(not(feature = "std"))]
-use once_cell::race::OnceBox as OnceCell;
-
 pub use api::build_type::{CustomType, TypeBuilder};
 #[cfg(not(feature = "no_custom_syntax"))]
 pub use api::custom_syntax::Expression;