diff --git a/Cargo.lock b/Cargo.lock
index ed0e878..418d039 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -349,7 +349,7 @@ dependencies = [
 
 [[package]]
 name = "grammalecte_client"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "env_logger",
  "log",
diff --git a/src/lib.rs b/src/lib.rs
index 1f26d4b..303232f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -270,7 +270,7 @@ pub struct GrammarError {
     #[serde(rename = "sType")]
     pub rule_type: String,
     #[serde(rename = "aColor")]
-    pub rule_underline_color: Vec<u8>,
+    pub rule_underline_color: Option<Vec<u8>>,
     #[serde(rename = "sMessage")]
     pub message: String,
     #[serde(rename = "aSuggestions")]
@@ -342,14 +342,14 @@ impl GrammalecteClient {
 
     /// Run spell check on text
     pub async fn spell_check(&self, text: &str) -> Result<CheckResult, Box<dyn Error>> {
-        self.spell_check_with_options(text, HashMap::new()).await
+        self.spell_check_with_options(text, &HashMap::new()).await
     }
 
     /// Run spell check with custom options
     pub async fn spell_check_with_options(
         &self,
         text: &str,
-        options: HashMap<GramOpt, bool>,
+        options: &HashMap<GramOpt, bool>,
     ) -> Result<CheckResult, Box<dyn Error>> {
         let url = format!("{}/gc_text/fr", self.base_url);
         log::debug!("Will use URL {} for spell check", url);
@@ -421,7 +421,7 @@ mod test {
         opts.insert(GramOpt::EspacesInsecables, false);
         let res = GrammalecteClient::start_server()
             .unwrap()
-            .spell_check_with_options(msg, opts)
+            .spell_check_with_options(msg, &opts)
             .await
             .unwrap();
         println!("RESULT = {:#?}", res);
diff --git a/src/server.rs b/src/server.rs
index 01b75f1..5305225 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -50,6 +50,7 @@ impl EmbeddedServer {
             .arg("-p")
             .arg(port.to_string())
             .stdout(Stdio::null())
+            .stderr(Stdio::null())
             .spawn()?;
 
         wait_for_port(port)?;