Hi there! I can help you with retrieving your lost calendar events after the iPhone update, and we can definitely look into backing up your older phone too. Let's go step by step.

### Recovering Your Lost Calendar Events

1. Check iCloud: First, if you have been using iCloud to sync your calendar, you might be able to restore your calendars directly from there. You can do this by:
- Going to iCloud.com and signing in to your Apple Account.
- Navigate to the Calendar section, and see if you can access your events there.

2. Restore Calendars: If the first step doesn’t help, you can try restoring deleted calendars directly from iCloud:
- While logged into iCloud.com, look for an option that may say ‘Restore Calendars’ or check out this Apple Support guide which can walk you through the steps.

3. Device Sync: If you have already tried using iCloud and it didn't work, try logging out of your iCloud account on all devices and logging back in. Sometimes, re-establishing a connection can restore missing data as well.

### Backup Your Older Phone

To prepare for backing up your older phone:

- Connect to iTunes: Make sure you have the latest version of iTunes installed on your Windows PC.
- Connect Your Phone: Use a USB cable to connect your older iPhone to your PC.
- Back Up:
- Open iTunes and select your device from the top left.
- Click on "Back Up Now."

This will create a backup of your older phone on your PC, which you can later restore to a newer device if needed.

### Further Steps

If you don't find your lost events through iCloud or they still aren't syncing back, tools like MobileTrans or.other iPhone data recovery software can be options to explore.

Are you satisfied with the solution I provided or do you need further assistance with any of these steps?