Photo Library on Mac Book Pro

Do you have iCloud Photos turned on in both your iPhone and your MacBook Pro? If so all photos should automatically sync with iCloud and both devices.

Regarding further software upgrades, what model year is your MacBook Pro?

The model year of a MacBook Pro is available at Apple menu > About This Mac.

An early 2015 through 2016 MacBook Pro can be upgraded to the latest version of Monterey macOS 12. See: How to download macOS - Apple Support

A 2017 or later MacBook Pro can be upgraded to the current version of Ventura macOS 13. See: How to upgrade to macOS Ventura - Apple Support

I don't remember if iPhoto supports iCloud Photos but you can only have one photo library syncing with iCloud Photos. Other than that, you cloud continue to use iPhotos as far as I know, but you would need to add any new photos to both and any edits to both. Personally, I would quit using iPhotos. It hasn't been updated in 8 years. I'm sure there must be something in iPhotos that some like better than Photos but I can't personally attest to that as I quit using it 8 years ago.

If you haven't moved the photos from iPhoto to Photos, I would recommend doing it soon. It can be done using the method I posted above when running Monterey or earlier but if you at some point get a Mac with Ventura or later that transition option is not supported.

Sorry, I thought I had posted that.

With Monterey and earlier you can hold down the option key while opening the Photos app and it will give you the option to select your iPhotos library and will then open it and convert it to Photos.

With Ventura, that option is no longer there. There is still a way to import iPhotos to Photos but you will lose your albums and events.