diff --git a/Cargo.toml b/Cargo.toml
index d29a58c..3650b04 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,10 +11,14 @@ keywords = ["optimizer", "optimization", "constrained", "derivative-free"]
 categories = ["algorithms", "api-bindings", "science"]
 documentation = "https://docs.rs/cobyla"
 
+[features]
+serde1 = ["dep:serde", "argmin/serde1"]
+
 [dependencies]
+serde = { version = "1", features = ["derive"], optional = true }
 libc = "0.2"
-argmin = "0.8.0"
-serde = "1"
+argmin-observer-slog = "0.1"
+argmin = "0.10"
 instant = "0.1"
 
 [dev-dependencies]
diff --git a/examples/paraboloid.rs b/examples/paraboloid.rs
index 9ff3616..7d6322f 100644
--- a/examples/paraboloid.rs
+++ b/examples/paraboloid.rs
@@ -1,5 +1,6 @@
-use argmin::core::observers::{ObserverMode, SlogLogger};
+use argmin::core::observers::ObserverMode;
 use argmin::core::{CostFunction, Error, Executor};
+use argmin_observer_slog::SlogLogger;
 use cobyla::{minimize, CobylaSolver, Func, RhoBeg, StopTols};
 
 /// Problem cost function
diff --git a/src/cobyla_solver.rs b/src/cobyla_solver.rs
index 48b36a0..3e4fe24 100644
--- a/src/cobyla_solver.rs
+++ b/src/cobyla_solver.rs
@@ -6,13 +6,15 @@ use crate::cobyla_state::*;
 use std::mem::ManuallyDrop;
 
 use argmin::core::{CostFunction, Problem, Solver, State, TerminationStatus, KV};
+#[cfg(feature = "serde1")]
 use serde::{Deserialize, Serialize};
 
 /// [Argmin Solver](https://www.argmin-rs.org/book/index.html) which implements COBYLA method.
 ///
 /// ```
 /// use argmin::core::{CostFunction, Error, Executor};
-/// use argmin::core::observers::{ObserverMode, SlogLogger};
+/// use argmin::core::observers::{ObserverMode};
+/// use argmin_observer_slog::SlogLogger;
 /// use cobyla::CobylaSolver;
 ///
 /// struct ParaboloidProblem;
@@ -40,7 +42,7 @@ use serde::{Deserialize, Serialize};
 ///
 /// println!("Result of COBYLA:\n{}", res);
 /// ```
-#[derive(Clone, Serialize, Deserialize)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
 pub struct CobylaSolver {
     /// Initial guess for x value
     x0: Vec<f64>,
diff --git a/src/cobyla_state.rs b/src/cobyla_state.rs
index a1f9c4d..c38208b 100644
--- a/src/cobyla_state.rs
+++ b/src/cobyla_state.rs
@@ -1,6 +1,7 @@
 use crate::cobyla::cobyla_context_t;
 /// Implementation of `argmin::IterState` for Cobyla optimizer
 use argmin::core::{Problem, State, TerminationReason, TerminationStatus};
+#[cfg(feature = "serde1")]
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::mem::ManuallyDrop;
@@ -24,7 +25,8 @@ use std::mem::ManuallyDrop;
 /// * termination status
 /// * COBYLA specific parameters: rhobeg, rhoend, iprint, maxfun
 ///
-#[derive(Clone, Debug, Default, Serialize, Deserialize)]
+#[derive(Clone, Debug, Default)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
 pub struct CobylaState {
     /// Current parameter vector
     pub param: Option<Vec<f64>>,
@@ -68,7 +70,7 @@ pub struct CobylaState {
     /// Cost function calls budget
     pub maxfun: i32,
 
-    #[serde(skip)]
+    #[cfg_attr(feature = "serde1", serde(skip))]
     pub cobyla_context: Option<ManuallyDrop<*mut cobyla_context_t>>,
 }
 
@@ -83,7 +85,7 @@ where
     ///
     /// ```
     /// # use argmin::core::{IterState, State};
-    /// # let state: IterState<Vec<f64>, (), (), (), f64> = IterState::new();
+    /// # let state: IterState<Vec<f64>, (), (), (), (), f64> = IterState::new();
     /// # let param_old = vec![1.0f64, 2.0f64];
     /// # let state = state.param(param_old);
     /// # assert!(state.prev_param.is_none());
@@ -529,7 +531,7 @@ impl State for CobylaState {
     ///
     /// ```
     /// # use argmin::core::{IterState, State, ArgminFloat, TerminationStatus};
-    /// # let mut state: IterState<Vec<f64>, (), (), (), f64> = IterState::new();
+    /// # let mut state: IterState<Vec<f64>, (), (), (), (), f64> = IterState::new();
     /// let termination_status = state.get_termination_status();
     /// # assert_eq!(*termination_status, TerminationStatus::NotTerminated);
     /// ```
@@ -543,7 +545,7 @@ impl State for CobylaState {
     ///
     /// ```
     /// # use argmin::core::{IterState, State, ArgminFloat, TerminationReason};
-    /// # let mut state: IterState<Vec<f64>, (), (), (), f64> = IterState::new();
+    /// # let mut state: IterState<Vec<f64>, (), (), (), (), f64> = IterState::new();
     /// let termination_reason = state.get_termination_reason();
     /// # assert_eq!(termination_reason, None);
     /// ```