Airplay 10.7.5 and 10.9.3

I have a Macbook running 10.7.5 and an iMac running 10.9.3. I have enabled Airdrop on the 10.7 laptop and it sees the iMac and Airdrop works fine on the 10.7 laptop. When I use it on the laptop I see a notification on the iMac and am able to save the sent files on the iMac.

The iMac does not see the laptop and the laptop doesn't appear on the airdrop screen of the iMac.

Any suggestions as to how to get the iMac to recognize the laptop?

Thanks for your help