Fix condition

app/Models/Company.php

@@ -380,4 +380,21 @@ class Company extends Model implements HasMedia
             $model->taxes()->delete();
         }
     }
+
+    public function hasTransactions()
+    {
+        if (
+            $this->customers()->exists() ||
+            $this->items()->exists() ||
+            $this->invoices()->exists() ||
+            $this->estimates()->exists() ||
+            $this->expenses()->exists() ||
+            $this->payments()->exists() ||
+            $this->recurringInvoices()->exists()
+        ) {
+            return true;
+        }
+
+        return false;
+    }
 }

app/Models/Currency.php

@@ -12,56 +12,4 @@ class Currency extends Model
     protected $guarded = [
         'id'
     ];
-
-    public function customers()
-    {
-        return $this->hasMany(Customer::class);
-    }
-
-    public function items()
-    {
-        return $this->hasMany(Item::class);
-    }
-
-    public function invoices()
-    {
-        return $this->hasMany(Invoice::class);
-    }
-
-    public function estimates()
-    {
-        return $this->hasMany(Estimate::class);
-    }
-
-    public function expenses()
-    {
-        return $this->hasMany(Expense::class);
-    }
-
-    public function payments()
-    {
-        return $this->hasMany(Payment::class);
-    }
-
-    public function recurringInvoices()
-    {
-        return $this->hasMany(RecurringInvoice::class);
-    }
-
-    public function checkTransactions()
-    {
-        if (
-            $this->customers()->exists() ||
-            $this->items()->exists() ||
-            $this->invoices()->exists() ||
-            $this->estimates()->exists() ||
-            $this->expenses()->exists() ||
-            $this->payments()->exists() ||
-            $this->recurringInvoices()->exists()
-        ) {
-            return true;
-        }
-
-        return false;
-    }
 }

app/Models/RecurringInvoice.php

@@ -307,7 +307,7 @@ class RecurringInvoice extends Model
 
         $days = CompanySetting::getSetting('invoice_due_date_days', $this->company_id);
 
-        if ($days == "null") {
+        if (! $days || $days == "null") {
             $days = 7;
         }