diff --git a/plugins/trainingsplan/static/index.html b/plugins/trainingsplan/static/index.html
index 9c6ece2..0e924fb 100644
--- a/plugins/trainingsplan/static/index.html
+++ b/plugins/trainingsplan/static/index.html
@@ -129,7 +129,19 @@
 
 const $ = (id) => document.getElementById(id);
 const $$ = (sel, root = document) => Array.from(root.querySelectorAll(sel));
-const api = (path) => window.BT ? BT.api(path) : fetch(path).then((r) => r.json());
+const api = async (path, options = {}) => {
+  if (window.BT) return BT.api(path, options);
+  const opts = {...options};
+  if (opts.body !== undefined && !(opts.body instanceof FormData)) {
+    opts.headers = {"Content-Type": "application/json", ...(opts.headers || {})};
+  }
+  const response = await fetch(path, opts);
+  const text = await response.text();
+  let payload = {};
+  try { payload = text ? JSON.parse(text) : {}; } catch (_) { payload = {raw: text}; }
+  if (!response.ok) throw new Error(payload.error || payload.detail || `HTTP ${response.status}`);
+  return payload;
+};
 const esc = (value) => window.BT ? BT.escape(value) : String(value ?? "").replace(/[&<>"']/g, (ch) => ({"&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;"}[ch]));
 const uid = (prefix) => `${prefix}-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 8)}`;
 
diff --git a/plugins/trainingstracker/tests/test_app.py b/plugins/trainingstracker/tests/test_app.py
index b844b2c..9f3d8ee 100644
--- a/plugins/trainingstracker/tests/test_app.py
+++ b/plugins/trainingstracker/tests/test_app.py
@@ -52,6 +52,14 @@ def sample_plan() -> dict:
                     "warmup": {"items": ["Mobilisieren"]},
                     "cooldown": {"items": ["Atmen"]},
                     "exercises": [{"id": "item-1", "exercise_id": "exercise-push"}],
+                },
+                {
+                    "id": "day-2",
+                    "num": 2,
+                    "name": "Tag 2",
+                    "warmup": {"items": []},
+                    "cooldown": {"items": []},
+                    "exercises": [{"id": "item-2", "exercise_id": "exercise-push"}],
                 }
             ],
         },
@@ -79,6 +87,14 @@ def sample_plan() -> dict:
                     "warmup": {"items": ["Mobilisieren"]},
                     "cooldown": {"items": ["Atmen"]},
                     "exercises": [{"id": "item-1", "exercise_id": "exercise-push"}],
+                },
+                {
+                    "id": "day-2",
+                    "num": 2,
+                    "name": "Tag 2",
+                    "warmup": {"items": []},
+                    "cooldown": {"items": []},
+                    "exercises": [{"id": "item-2", "exercise_id": "exercise-push"}],
                 }
             ],
         },
@@ -124,6 +140,12 @@ def test_current_progression_update_writes_config_and_draft(tmp_path: Path):
     payload = response.get_json()
     exercise = payload["plan"]["config"]["exercises"][0]
     assert exercise["current_progression_id"] == "progression-negative"
+    day_progressions = [
+        item["exercise"]["current_progression"]["id"]
+        for day in payload["plan"]["config"]["days"]
+        for item in day["exercises"]
+    ]
+    assert day_progressions == ["progression-negative", "progression-negative"]
 
     saved = json.loads(plan_file.read_text(encoding="utf-8"))
     assert saved["config"]["exercises"][0]["current_progression_id"] == "progression-negative"