diff --git a/src-tauri/src/api_client.rs b/src-tauri/src/api_client.rs
index 07714a6..e9e0b84 100644
--- a/src-tauri/src/api_client.rs
+++ b/src-tauri/src/api_client.rs
@@ -934,7 +934,7 @@ impl ApiClient {
               BrowserRelease {
                 version: version.clone(),
                 date: "".to_string(), // Cache doesn't store dates
-                is_prerelease: false, // Assume all archived versions are stable
+                is_prerelease: is_nightly_version(&version),
                 download_url: Some(format!(
                   "{}/{version}/tor-browser-macos-{version}.dmg",
                   self.tor_archive_base
diff --git a/src-tauri/src/browser_version_service.rs b/src-tauri/src/browser_version_service.rs
index de8f36a..05b15a3 100644
--- a/src-tauri/src/browser_version_service.rs
+++ b/src-tauri/src/browser_version_service.rs
@@ -360,7 +360,7 @@ impl BrowserVersionService {
             if let Some(release) = releases.iter().find(|r| r.version == version) {
               BrowserVersionInfo {
                 version: release.version.clone(),
-                is_prerelease: release.is_prerelease,
+                is_prerelease: crate::api_client::is_nightly_version(&version),
                 date: release.date.clone(),
               }
             } else {