diff --git a/Source/package.json b/Source/package.json
index e2d8853..d9b8289 100644
--- a/Source/package.json
+++ b/Source/package.json
@@ -141,11 +141,11 @@
         "ts-deepmerge": "8.0.0"
     },
     "devDependencies": {
-        "@cratis/arc.vite": "^20.49.2"
+        "@cratis/arc.vite": "^21.0.2"
     },
     "peerDependencies": {
-        "@cratis/arc": "^20.3.1",
-        "@cratis/arc.react": "^20.3.1",
+        "@cratis/arc": ">=20.3.1 <22",
+        "@cratis/arc.react": ">=20.3.1 <22",
         "@cratis/fundamentals": "^7.10.3",
         "react": "^19.0.0",
         "react-dom": "^19.0.0",
diff --git a/Source/vite.config.ts b/Source/vite.config.ts
index 66f2d99..bf33b7a 100644
--- a/Source/vite.config.ts
+++ b/Source/vite.config.ts
@@ -31,7 +31,10 @@ export default defineConfig({
     test: {
         globals: true,
         environment: 'node',
-        isolate: false,
+        // Isolated, because several spec files mock the same module (@cratis/arc.react/dialogs) with
+        // their own spies. With a shared module graph whichever file loaded first wins and the others
+        // observe zero calls, which showed up as an intermittent "expected one closeDialog call, got 0".
+        isolate: true,
         fileParallelism: false,
         pool: 'threads',
         coverage: {
diff --git a/package.json b/package.json
index d0bd334..0d17475 100644
--- a/package.json
+++ b/package.json
@@ -28,9 +28,9 @@
     "version": "0.0.0",
     "packageManager": "yarn@4.5.3",
     "devDependencies": {
-        "@cratis/arc": "^20.49.2",
-        "@cratis/arc.react": "^20.49.2",
-        "@cratis/arc.vite": "^20.49.2",
+        "@cratis/arc": "^21.0.2",
+        "@cratis/arc.react": "^21.0.2",
+        "@cratis/arc.vite": "^21.0.2",
         "@eslint/eslintrc": "^3.3.5",
         "@eslint/js": "^10.0.1",
         "@rollup/plugin-node-resolve": "^16.0.3",