Address book issues

I use a Macbook OS 10.7.5, iPhone 6 and Macbook pro. My problem is suddenly I cannot use my address book on the Macbook OS 10.7.5. Message says address book 4.0.6 won't work with this version. Not sure why it changed or what happened can anyone help? I don't even know what 4.0.6 is compatible with.

You're behind the times. The address book.app was replaced by the "contacts.app" in later versions of OS X. Also the copy of address book you're using is an older version and will not work in Lion (OS X 10.7.5) You can possibly update the address book using software update from the Mac App Store. And if you wish to sync contacts to your iPhone 6 from your Mac using iCloud, you will need to update.

Thanks for the reply. Since my "address book" has been working for the last year or so I went into the applications and found 2 address books - the correct version was there along with the old one. Somehow the icon got associated with the old one. Not sure how that occurred but I threw it out and all is well. I could not find any info on what version I should have so I didn't know what was old or new. Thanks again