IOS – iPhone 7 Plus not appearing on Airdrop

Thanks to the development of Bluetooth 4.0 and BLE, it is not possible to airdrop between newer iOS devices and older (pre-retina, I believe) MacBooks.

This is because the standards are incompatible, while 'legacy airdrop' is still an option for MacBook-to-MacBook communication, it appears iOS devices do not have this functionality. A more in depth discussion can be found on Apple's forums, and a lengthy discussion on whether an upgrade is possible or should be attempted here.

I finally found a solution that worked for me. This seems unrelated but it definitely was my issue. It also fixed my issue with Apple Watch not being able to unlock my Mac. Below is what worked for me.

On your Mac:

1. Open up Messages App
2. Go to Messages > Preferences
3. Select Accounts Tab
4. Select Blocked Tab
5. Locate and delete any instances of your own phone number and/or email addresses
6. Close and wait ~5 minutes for iCloud to sync the changes across all your devices

On IOS:

1. Go to Settings -> Messages -> Blocked
2. Same as step 5 and 6 above

After performing those steps Airdrop worked perfectly across all devices and, as a bonus, I was able to unlock my Mac with my Apple Watch again (I was previously getting "your mac was unable to communicate with your apple watch" error / "IDS device not cloud paired").

Hope this helps others!