diff --git a/crates/ahfail-ui/src/update.rs b/crates/ahfail-ui/src/update.rs
index 93310b8..41ae421 100644
--- a/crates/ahfail-ui/src/update.rs
+++ b/crates/ahfail-ui/src/update.rs
@@ -1,5 +1,6 @@
 use std::path::PathBuf;
 use std::process::Command;
+use std::sync::atomic::{AtomicBool, Ordering};
 use std::time::SystemTime;
 use std::fs;
 
@@ -9,6 +10,9 @@ const UPDATE_NOTIFY_MSG: &str =
     "Update available — visit https://gitea.weircon.dk/agw/gtk-ahfail/releases";
 const CHECK_INTERVAL_SECS: u64 = 86_400;
 
+// Guards against multiple windows spawning duplicate checks on the same failure.
+static CHECK_IN_FLIGHT: AtomicBool = AtomicBool::new(false);
+
 pub fn is_newer(latest: &str, current: &str) -> bool {
     let parse = |s: &str| -> Option<(u32, u32, u32)> {
         let s = s.trim_start_matches('v');
@@ -25,7 +29,10 @@ pub fn is_newer(latest: &str, current: &str) -> bool {
 fn cache_file() -> PathBuf {
     let dir = std::env::var("HOME")
         .map(|h| PathBuf::from(h).join(".cache/ahfail"))
-        .unwrap_or_else(|_| PathBuf::from("/tmp/ahfail-cache"));
+        .unwrap_or_else(|_| {
+            let uid = unsafe { libc::getuid() };
+            PathBuf::from(format!("/tmp/ahfail-cache-{uid}"))
+        });
     let _ = fs::create_dir_all(&dir);
     dir.join("last_update_check")
 }
@@ -51,7 +58,7 @@ fn send_notification() {
     #[cfg(target_os = "linux")]
     let _ = Command::new("notify-send")
         .args(["ahfail", UPDATE_NOTIFY_MSG])
-        .spawn();
+        .status();
 
     #[cfg(target_os = "macos")]
     let _ = Command::new("osascript")
@@ -59,7 +66,7 @@ fn send_notification() {
             "display notification \"{}\" with title \"ahfail\"",
             UPDATE_NOTIFY_MSG
         )])
-        .spawn();
+        .status();
 }
 
 /// Run in a background thread. Checks Gitea for a newer release and sends a
@@ -67,10 +74,28 @@ fn send_notification() {
 /// Fails silently on any error.
 pub fn check_for_update(current_version: &str) {
     if rate_limited() { return; }
+    // Prevent concurrent threads (e.g. multi-monitor) from all firing at once.
+    if CHECK_IN_FLIGHT.compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst).is_err() {
+        return;
+    }
+
+    let agent = ureq::AgentBuilder::new()
+        .timeout_connect(std::time::Duration::from_secs(5))
+        .timeout_read(std::time::Duration::from_secs(10))
+        .build();
+
+    let Ok(resp) = agent.get(GITEA_API).call() else {
+        CHECK_IN_FLIGHT.store(false, Ordering::SeqCst);
+        return;
+    };
     touch_cache();
 
-    let Ok(resp) = ureq::get(GITEA_API).call() else { return };
-    let Ok(body) = resp.into_string() else { return };
+    let Ok(body) = resp.into_string() else {
+        CHECK_IN_FLIGHT.store(false, Ordering::SeqCst);
+        return;
+    };
+
+    CHECK_IN_FLIGHT.store(false, Ordering::SeqCst);
 
     if let Some(tag) = extract_tag_name(&body) {
         if is_newer(&tag, current_version) {
@@ -80,8 +105,11 @@ pub fn check_for_update(current_version: &str) {
 }
 
 fn extract_tag_name(json: &str) -> Option<String> {
-    let key = "\"tag_name\":\"";
-    let start = json.find(key)? + key.len();
-    let end = json[start..].find('"')? + start;
-    Some(json[start..end].to_string())
+    // Handle both compact ("tag_name":"v1.0") and spaced ("tag_name": "v1.0") JSON.
+    let key = "\"tag_name\"";
+    let after_key = json.find(key)? + key.len();
+    let rest = json[after_key..].trim_start_matches(|c: char| c == ':' || c.is_ascii_whitespace());
+    let rest = rest.strip_prefix('"')?;
+    let end = rest.find('"')?;
+    Some(rest[..end].to_string())
 }
diff --git a/crates/ahfail-ui/tests/update_tests.rs b/crates/ahfail-ui/tests/update_tests.rs
index 7d5d624..612c5a2 100644
--- a/crates/ahfail-ui/tests/update_tests.rs
+++ b/crates/ahfail-ui/tests/update_tests.rs
@@ -12,3 +12,9 @@ fn newer_version_detected() {
 fn strips_v_prefix() {
     assert!(is_newer("0.2.0", "0.1.0"));
 }
+
+#[test]
+fn multi_digit_minor_version() {
+    assert!(is_newer("v0.10.0", "v0.9.0"));
+    assert!(!is_newer("v0.9.0", "v0.10.0"));
+}