You can upload transactions that are beyond 90 days using the web connect process. This allows you to obtain a file with only needed information directly from your bank website and upload it to QuickBooks Online. I'll show you how:
Navigate to your financial institution's website and sign in. Head to the transaction list and filter it to only include transactions.
Look for a Download ⬇ button. If offered different file types, select either QuickBooks Online (.QBO) or (.CSV).
Head back to QBO and sign in. Go to the Banking tab, select the drop-down ▼ next to Update, and click File Upload.
Select Browse, find the file you downloaded and follow the on-screen instructions to map and upload your transactions.