diff --git a/geo-types/Cargo.toml b/geo-types/Cargo.toml
index ecf900d047..d5a310729e 100644
--- a/geo-types/Cargo.toml
+++ b/geo-types/Cargo.toml
@@ -12,7 +12,7 @@ edition = "2021"
 
 [features]
 default = ["std"]
-std = ["approx/std", "num-traits/std", "serde/std"]
+std = ["approx?/std", "num-traits/std", "serde?/std"]
 # Prefer `use-rstar` feature rather than enabling rstar directly.
 # rstar integration relies on the optional approx crate, but implicit features cannot yet enable other features.
 # See: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#namespaced-features