diff --git a/Cargo.toml b/Cargo.toml
index cba3583..06de3cc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,10 @@ categories = ["aerospace", "aerospace::space-protocols", "no-std", "hardware-sup
 zerocopy = "0.6"
 crc = "3"
 delegate = ">=0.8, <0.11"
-thiserror = "1"
+
+[dependencies.thiserror]
+version = "1"
+optional = true
 
 [dependencies.num_enum]
 version = "0.6"
@@ -41,7 +44,7 @@ version = "1"
 
 [features]
 default = ["std"]
-std = ["chrono/std", "chrono/clock", "alloc"]
+std = ["chrono/std", "chrono/clock", "alloc", "thiserror"]
 serde = ["dep:serde", "chrono/serde"]
 alloc = ["postcard/alloc", "chrono/alloc"]
 
diff --git a/src/lib.rs b/src/lib.rs
index 094322d..8370d45 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -65,8 +65,7 @@ use crate::ecss::CCSDS_HEADER_LEN;
 use core::fmt::{Debug, Display, Formatter};
 use crc::{Crc, CRC_16_IBM_3740};
 use delegate::delegate;
-#[cfg(not(feature = "std"))]
-use num_traits::Unsigned;
+
 #[cfg(feature = "std")]
 use std::error::Error;
 
diff --git a/src/time/cuc.rs b/src/time/cuc.rs
index 3f93080..22d3b6f 100644
--- a/src/time/cuc.rs
+++ b/src/time/cuc.rs
@@ -3,7 +3,6 @@
 //!
 //! The core data structure to do this is the [TimeProviderCcsdsEpoch] struct.
 use super::*;
-use crate::time::std_mod::StdTimestampError;
 use chrono::Datelike;
 use core::fmt::Debug;
 use core::ops::{Add, AddAssign};