diff --git a/db.go b/db.go
index a313020..1958d37 100644
--- a/db.go
+++ b/db.go
@@ -29,6 +29,10 @@ func InitDatabase() error {
 
 	db = database
 
+	// SQLite Pragmas setzen
+	db.MustExec("PRAGMA journal_mode=WAL")
+	db.MustExec("PRAGMA foreign_keys=ON")
+
 	// Schema erstellen
 	if err := createSchema(); err != nil {
 		return fmt.Errorf("failed to create schema: %w", err)
diff --git a/frontend/package.json b/frontend/package.json
index 6c23523..086ed7b 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -9,19 +9,18 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "@types/react-router-dom": "^5.3.3",
-    "autoprefixer": "^10.4.24",
-    "postcss": "^8.5.6",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
-    "react-router-dom": "^7.13.0",
-    "tailwindcss": "^4.2.0"
+    "react-router-dom": "^6.26.0"
   },
   "devDependencies": {
     "@types/react": "^18.0.17",
     "@types/react-dom": "^18.0.6",
-    "@vitejs/plugin-react": "^2.0.1",
-    "typescript": "^4.6.4",
-    "vite": "^3.0.7"
+    "@vitejs/plugin-react": "^4.3.0",
+    "autoprefixer": "^10.4.24",
+    "postcss": "^8.5.6",
+    "tailwindcss": "^3.4.0",
+    "typescript": "^5.5.0",
+    "vite": "^5.4.0"
   }
 }
diff --git a/frontend/postcss.config.js b/frontend/postcss.config.js
index e99ebc2..2e7af2b 100644
--- a/frontend/postcss.config.js
+++ b/frontend/postcss.config.js
@@ -3,4 +3,4 @@ export default {
     tailwindcss: {},
     autoprefixer: {},
   },
-}
\ No newline at end of file
+}
diff --git a/frontend/src/components/AdditivePicker.tsx b/frontend/src/components/AdditivePicker.tsx
index f5b66fa..e01d5e2 100644
--- a/frontend/src/components/AdditivePicker.tsx
+++ b/frontend/src/components/AdditivePicker.tsx
@@ -7,33 +7,8 @@ interface AdditivePickerProps {
   className?: string;
 }
 
-// Deutsche Namen für häufige Zusatzstoffe (E-Nummern)
-const ADDITIVE_NAMES: Record<string, string> = {
-  '1': 'Farbstoff',
-  '2': 'Konservierungsstoff', 
-  '3': 'Antioxidationsmittel',
-  '4': 'Geschmacksverstärker',
-  '5': 'Geschwefelt',
-  '6': 'Geschwärzt',
-  '7': 'Gewachst',
-  '8': 'Phosphat',
-  '9': 'Süßungsmittel',
-  '10': 'Phenylalaninquelle',
-  '11': 'Koffeinhaltig',
-  '12': 'Chininhaltig',
-  '13': 'Alkoholhaltig',
-  '14': 'Nitritpökelsalz',
-  '15': 'Milchsäure',
-  '16': 'Citronensäure',
-  '17': 'Ascorbinsäure',
-  '18': 'Tocopherol',
-  '19': 'Lecithin',
-  '20': 'Johannisbrotkernmehl',
-  '21': 'Guarkernmehl',
-  '22': 'Xanthan',
-  '23': 'Carrageen',
-  '24': 'Agar'
-};
+// Die Zusatzstoffe kommen direkt aus der DB mit id + name,
+// daher wird hier kein separates Mapping benötigt.
 
 export function AdditivePicker({ additives, selectedIds, onChange, className = '' }: AdditivePickerProps) {
   const handleToggle = (additiveId: string) => {
@@ -68,7 +43,7 @@ export function AdditivePicker({ additives, selectedIds, onChange, className = '
       >
         {sortedAdditives.map(additive => {
           const isSelected = selectedIds.includes(additive.id);
-          const displayName = ADDITIVE_NAMES[additive.id] || additive.name;
+          const displayName = additive.name;
           
           return (
             <label
diff --git a/frontend/src/components/AllergenPicker.tsx b/frontend/src/components/AllergenPicker.tsx
index 7c8df66..032306f 100644
--- a/frontend/src/components/AllergenPicker.tsx
+++ b/frontend/src/components/AllergenPicker.tsx
@@ -65,7 +65,7 @@ export function AllergenPicker({ allergens, selectedIds, onChange, className = '
                 type="checkbox"
                 checked={isSelected}
                 onChange={() => handleToggle(allergen.id)}
-                className="hidden"
+                className="sr-only"
                 aria-describedby={`allergen-${allergen.id}-description`}
               />
               
diff --git a/frontend/src/components/ProductForm.tsx b/frontend/src/components/ProductForm.tsx
index 9b6274a..a81129d 100644
--- a/frontend/src/components/ProductForm.tsx
+++ b/frontend/src/components/ProductForm.tsx
@@ -82,8 +82,24 @@ export function ProductForm({
 
   const isEditing = !!product;
 
+  // Escape-Taste schließt den Dialog
+  useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') {
+        onCancel();
+      }
+    };
+    document.addEventListener('keydown', handleKeyDown);
+    return () => document.removeEventListener('keydown', handleKeyDown);
+  }, [onCancel]);
+
   return (
-    <div className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50">
+    <div 
+      className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50"
+      role="dialog"
+      aria-modal="true"
+      aria-label={isEditing ? 'Produkt bearbeiten' : 'Neues Produkt erstellen'}
+    >
       <div className="bg-white rounded-lg shadow-xl max-w-4xl w-full max-h-[90vh] overflow-y-auto">
         <form onSubmit={handleSubmit}>
           {/* Header */}
diff --git a/frontend/src/components/ProductSearch.tsx b/frontend/src/components/ProductSearch.tsx
index 21980da..0120c48 100644
--- a/frontend/src/components/ProductSearch.tsx
+++ b/frontend/src/components/ProductSearch.tsx
@@ -24,6 +24,7 @@ export function ProductSearch({
   const [selectedIndex, setSelectedIndex] = useState(-1);
   const inputRef = useRef<HTMLInputElement>(null);
   const listRef = useRef<HTMLUListElement>(null);
+  const containerRef = useRef<HTMLDivElement>(null);
 
   // Filter products based on search query
   const filteredProducts = query.trim() 
@@ -95,7 +96,7 @@ export function ProductSearch({
   // Close dropdown when clicking outside
   useEffect(() => {
     const handleClickOutside = (event: MouseEvent) => {
-      if (inputRef.current && !inputRef.current.contains(event.target as Node)) {
+      if (containerRef.current && !containerRef.current.contains(event.target as Node)) {
         setIsOpen(false);
         setSelectedIndex(-1);
       }
@@ -116,7 +117,7 @@ export function ProductSearch({
   const showResults = isOpen && (filteredProducts.length > 0 || (allowCustom && query.trim()));
 
   return (
-    <div className={`relative ${className}`} role="combobox" aria-expanded={isOpen}>
+    <div ref={containerRef} className={`relative ${className}`} role="combobox" aria-expanded={isOpen}>
       <input
         ref={inputRef}
         type="text"
diff --git a/frontend/src/components/Sidebar.tsx b/frontend/src/components/Sidebar.tsx
index ae5de33..b96bc59 100644
--- a/frontend/src/components/Sidebar.tsx
+++ b/frontend/src/components/Sidebar.tsx
@@ -204,7 +204,7 @@ export function Sidebar({
                         : 'text-gray-700 hover:bg-gray-100 hover:text-gray-900'
                     }`
                   }
-                  aria-current={({ isActive }) => isActive ? 'page' : undefined}
+                  end={item.to === '/'}
                 >
                   {item.icon}
                   <span className="ml-3">{item.name}</span>
@@ -257,7 +257,13 @@ function CopyWeekDialog({ targetYear, targetWeek, onCopy, onCancel }: CopyWeekDi
   };
 
   return (
-    <div className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50">
+    <div 
+      className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50"
+      role="dialog"
+      aria-modal="true"
+      aria-label="Kalenderwoche kopieren"
+      onKeyDown={(e) => { if (e.key === 'Escape') onCancel(); }}
+    >
       <div className="bg-white rounded-lg shadow-xl max-w-md w-full">
         <form onSubmit={handleSubmit}>
           <div className="p-6">
diff --git a/frontend/src/components/SpecialDayDialog.tsx b/frontend/src/components/SpecialDayDialog.tsx
index 6689cde..5d3ac54 100644
--- a/frontend/src/components/SpecialDayDialog.tsx
+++ b/frontend/src/components/SpecialDayDialog.tsx
@@ -35,7 +35,13 @@ export function SpecialDayDialog({
   const isEditing = !!existingSpecialDay;
 
   return (
-    <div className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50">
+    <div 
+      className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50"
+      role="dialog"
+      aria-modal="true"
+      aria-label={`Sondertag für ${DAY_NAMES[day]}`}
+      onKeyDown={(e) => { if (e.key === 'Escape') onCancel(); }}
+    >
       <div className="bg-white rounded-lg shadow-xl max-w-md w-full">
         <form onSubmit={handleSubmit}>
           {/* Header */}
diff --git a/frontend/src/components/WeekPlanner.tsx b/frontend/src/components/WeekPlanner.tsx
index 04e326b..a51b60a 100644
--- a/frontend/src/components/WeekPlanner.tsx
+++ b/frontend/src/components/WeekPlanner.tsx
@@ -136,7 +136,7 @@ export function WeekPlanner({ year, week, className = '' }: WeekPlannerProps) {
   }
 
   return (
-    <div className={className}>
+    <div className={className} aria-live="polite">
       {/* Error Banner */}
       {error && (
         <div className="bg-red-50 border border-red-200 rounded-md p-4 mb-6">
diff --git a/frontend/src/hooks/useProducts.ts b/frontend/src/hooks/useProducts.ts
index bdf1206..efc51f5 100644
--- a/frontend/src/hooks/useProducts.ts
+++ b/frontend/src/hooks/useProducts.ts
@@ -124,22 +124,22 @@ export function useProducts() {
     const searchTerm = query.toLowerCase();
     return products.filter(product =>
       product.name.toLowerCase().includes(searchTerm) ||
-      product.allergens.some(a => a.name.toLowerCase().includes(searchTerm)) ||
-      product.additives.some(a => a.name.toLowerCase().includes(searchTerm))
+      (product.allergens || []).some(a => a.name.toLowerCase().includes(searchTerm)) ||
+      (product.additives || []).some(a => a.name.toLowerCase().includes(searchTerm))
     );
   };
 
   // Produkte nach Allergenen filtern
   const filterByAllergen = (allergenId: string): Product[] => {
     return products.filter(product =>
-      product.allergens.some(a => a.id === allergenId)
+      (product.allergens || []).some(a => a.id === allergenId)
     );
   };
 
   // Produkte nach Zusatzstoffen filtern
   const filterByAdditive = (additiveId: string): Product[] => {
     return products.filter(product =>
-      product.additives.some(a => a.id === additiveId)
+      (product.additives || []).some(a => a.id === additiveId)
     );
   };
 
diff --git a/frontend/src/hooks/useWeekPlan.ts b/frontend/src/hooks/useWeekPlan.ts
index b3ae8c5..c49f0af 100644
--- a/frontend/src/hooks/useWeekPlan.ts
+++ b/frontend/src/hooks/useWeekPlan.ts
@@ -109,15 +109,12 @@ export function useWeekPlan(year: number, week: number) {
   // Eintrag bearbeiten
   const updateEntry = async (
     entryId: number,
-    day: WeekDay,
-    meal: MealType,
-    slot: number,
     productId?: number,
     customText?: string,
     groupLabel?: GroupLabel
   ): Promise<PlanEntry | null> => {
     try {
-      const updatedEntry = await UpdatePlanEntry(entryId, day, meal, slot, productId, customText, groupLabel);
+      const updatedEntry = await UpdatePlanEntry(entryId, productId, customText, groupLabel);
       
       // State aktualisieren
       setWeekPlan(prev => prev ? {
diff --git a/frontend/src/lib/weekHelper.ts b/frontend/src/lib/weekHelper.ts
index 085ff90..48e31e0 100644
--- a/frontend/src/lib/weekHelper.ts
+++ b/frontend/src/lib/weekHelper.ts
@@ -18,18 +18,22 @@ export function getWeekFromDate(date: Date): { year: number; week: number } {
   const tempDate = new Date(date.valueOf());
   const dayNum = (tempDate.getDay() + 6) % 7; // Montag = 0
   
+  // Zum Donnerstag der gleichen Woche gehen (ISO 8601)
   tempDate.setDate(tempDate.getDate() - dayNum + 3);
   const firstThursday = tempDate.valueOf();
-  tempDate.setMonth(0, 1);
+  // Das ISO-Jahr ist das Jahr des Donnerstags
+  const isoYear = tempDate.getFullYear();
   
-  if (tempDate.getDay() !== 4) {
-    tempDate.setMonth(0, 1 + ((4 - tempDate.getDay()) + 7) % 7);
+  // Ersten Donnerstag des ISO-Jahres finden
+  const jan1 = new Date(isoYear, 0, 1);
+  if (jan1.getDay() !== 4) {
+    jan1.setMonth(0, 1 + ((4 - jan1.getDay()) + 7) % 7);
   }
   
-  const week = 1 + Math.ceil((firstThursday - tempDate.valueOf()) / 604800000); // 7 * 24 * 3600 * 1000
+  const week = 1 + Math.ceil((firstThursday - jan1.valueOf()) / 604800000); // 7 * 24 * 3600 * 1000
   
   return {
-    year: tempDate.getFullYear(),
+    year: isoYear,
     week: week
   };
 }
@@ -38,14 +42,13 @@ export function getWeekFromDate(date: Date): { year: number; week: number } {
  * Berechnet das erste Datum einer Kalenderwoche
  */
 export function getDateFromWeek(year: number, week: number): Date {
-  const date = new Date(year, 0, 1);
-  const dayOfWeek = date.getDay();
-  const daysToMonday = dayOfWeek <= 4 ? dayOfWeek - 1 : dayOfWeek - 8;
+  // Find Jan 4 (always in ISO week 1) then find its Monday
+  const jan4 = new Date(year, 0, 4);
+  const dayOfWeek = (jan4.getDay() + 6) % 7; // Monday = 0
+  const monday = new Date(jan4);
+  monday.setDate(jan4.getDate() - dayOfWeek + (week - 1) * 7);
   
-  date.setDate(date.getDate() - daysToMonday);
-  date.setDate(date.getDate() + (week - 1) * 7);
-  
-  return date;
+  return monday;
 }
 
 /**
@@ -103,9 +106,10 @@ export function getPrevWeek(year: number, week: number): { year: number; week: n
  * Berechnet die Anzahl Kalenderwochen in einem Jahr
  */
 export function getWeeksInYear(year: number): number {
-  const dec31 = new Date(year, 11, 31);
-  const week = getWeekFromDate(dec31);
-  return week.year === year ? week.week : week.week - 1;
+  // Dec 28 is always in the last ISO week of its year
+  const dec28 = new Date(year, 11, 28);
+  const week = getWeekFromDate(dec28);
+  return week.week;
 }
 
 /**
diff --git a/main.go b/main.go
index 8d47f91..87c00e5 100644
--- a/main.go
+++ b/main.go
@@ -19,13 +19,6 @@ func main() {
 		log.Fatalf("Failed to initialize database: %v", err)
 	}
 
-	// Sicherstellen, dass die Datenbank ordnungsgemäß geschlossen wird
-	defer func() {
-		if err := CloseDatabase(); err != nil {
-			log.Printf("Error closing database: %v", err)
-		}
-	}()
-
 	// Create an instance of the app structure
 	app := NewApp()
 
diff --git a/models.go b/models.go
index 5b595cf..3d253ea 100644
--- a/models.go
+++ b/models.go
@@ -40,8 +40,8 @@ type WeekPlan struct {
 type PlanEntry struct {
 	ID         int      `json:"id" db:"id"`
 	WeekPlanID int      `json:"week_plan_id" db:"week_plan_id"`
-	Day        int      `json:"day" db:"day"` // 0=Mo, 1=Di, 2=Mi, 3=Do, 4=Fr
-	Meal       string   `json:"meal" db:"meal"` // 'breakfast' oder 'snack'
+	Day        int      `json:"day" db:"day"` // 1=Mo, 2=Di, 3=Mi, 4=Do, 5=Fr
+	Meal       string   `json:"meal" db:"meal"` // 'fruehstueck' oder 'vesper'
 	Slot       int      `json:"slot" db:"slot"` // Reihenfolge innerhalb des Tages
 	ProductID  *int     `json:"product_id" db:"product_id"`
 	Product    *Product `json:"product,omitempty"`
@@ -53,8 +53,8 @@ type PlanEntry struct {
 type SpecialDay struct {
 	ID         int    `json:"id" db:"id"`
 	WeekPlanID int    `json:"week_plan_id" db:"week_plan_id"`
-	Day        int    `json:"day" db:"day"` // 0=Mo, 1=Di, ...
-	Type       string `json:"type" db:"type"` // 'holiday' oder 'closed'
+	Day        int    `json:"day" db:"day"` // 1=Mo, 2=Di, ...
+	Type       string `json:"type" db:"type"` // 'feiertag' oder 'schliesstag'
 	Label      *string `json:"label" db:"label"` // z.B. "Neujahr", "Teamtag"
 }
 
diff --git a/seed.go b/seed.go
index dd505d8..2c887e0 100644
--- a/seed.go
+++ b/seed.go
@@ -145,7 +145,8 @@ func seedProducts() error {
 
 		// Produkt-ID ermitteln
 		var productID int64
-		if productID, err = result.LastInsertId(); err != nil {
+		productID, err = result.LastInsertId()
+		if err != nil || productID == 0 {
 			// Wenn INSERT OR IGNORE nichts eingefügt hat, ID über SELECT holen
 			err = tx.Get(&productID, "SELECT id FROM products WHERE name = ?", product.Name)
 			if err != nil {
diff --git a/updater.go b/updater.go
index 6dd673f..6940ca0 100644
--- a/updater.go
+++ b/updater.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"strconv"
 	"strings"
 	"time"
 )
@@ -79,7 +80,7 @@ func (u *Updater) DownloadUpdate(downloadURL string) error {
 // compareVersions vergleicht zwei Versionsstrings
 // Gibt -1 zurück wenn v1 < v2, 0 wenn v1 == v2, 1 wenn v1 > v2
 func compareVersions(v1, v2 string) int {
-	// Vereinfachter Versionsvergleich (nur für grundlegende Semantic Versioning)
+	// Semantic Versioning Vergleich mit numerischem Parsing
 	v1Parts := strings.Split(strings.TrimPrefix(v1, "v"), ".")
 	v2Parts := strings.Split(strings.TrimPrefix(v2, "v"), ".")
 
@@ -92,11 +93,22 @@ func compareVersions(v1, v2 string) int {
 	}
 
 	for i := 0; i < 3; i++ {
-		// Einfacher String-Vergleich (funktioniert für einstellige Zahlen)
-		if v1Parts[i] < v2Parts[i] {
+		n1, err1 := strconv.Atoi(v1Parts[i])
+		n2, err2 := strconv.Atoi(v2Parts[i])
+		if err1 != nil || err2 != nil {
+			// Fallback auf String-Vergleich
+			if v1Parts[i] < v2Parts[i] {
+				return -1
+			}
+			if v1Parts[i] > v2Parts[i] {
+				return 1
+			}
+			continue
+		}
+		if n1 < n2 {
 			return -1
 		}
-		if v1Parts[i] > v2Parts[i] {
+		if n1 > n2 {
 			return 1
 		}
 	}