diff --git a/app/Support/Models/AccountBalanceCalculator.php b/app/Support/Models/AccountBalanceCalculator.php
index aa264c3bb6..a0ac3e6c63 100644
--- a/app/Support/Models/AccountBalanceCalculator.php
+++ b/app/Support/Models/AccountBalanceCalculator.php
@@ -99,7 +99,7 @@ class AccountBalanceCalculator
         return $entry;
     }
 
-    private function optimizedCalculation(Collection $accounts, Carbon $notBefore = null): void
+    private function optimizedCalculation(Collection $accounts, ?Carbon $notBefore = null): void
     {
         Log::debug('start of optimizedCalculation');
         if ($accounts->count() > 0) {
@@ -121,7 +121,7 @@ class AccountBalanceCalculator
         if ($accounts->count() > 0) {
             $query->whereIn('transactions.account_id', $accounts->pluck('id')->toArray());
         }
-        if(null !== $notBefore) {
+        if (null !== $notBefore) {
             $notBefore->startOfDay();
             $query->where('transaction_journals.date', '>=', $notBefore);
         }
diff --git a/config/firefly.php b/config/firefly.php
index c8932fcb5a..6a7a0b3c1d 100644
--- a/config/firefly.php
+++ b/config/firefly.php
@@ -117,7 +117,7 @@ return [
         'expression_engine' => true,
         // see cer.php for exchange rates feature flag.
     ],
-    'version'                      => '6.1.20',
+    'version'                      => 'develop/2024-09-28',
     'api_version'                  => '2.1.0',
     'db_version'                   => 24,