Mirrored Site and Expired Domain

I’ve mirrored my original wordpress website (www.alivinglandscape.com) with my desired domain name, www.communitysoil.com.

I accidentally let my original domain name expire (yikes! lame move totally). While I’m trying to recover that domain, I have a question… Do I actually need it?

How can I change my website to the new domain? The mirror was my original fix, but I’d really like for everything to be connected to the new domain name. Can I just leave it as it is? What happens when I make changes or updates? It’s still accessing the original database, right? What happens if the original domain gets acquired by someone else? All my data should still live on my server, yes? It’s just an address, right?

Yes, a domain is just an address. If you do not recover your old domain, your data is not lost. It may just take time for your new web site to be indexed and for people who used to visit your old site to find the new one.

So, no - you no not need the old domain.
But it may be worth recovering for a year if you had lots of visitors you do not wish to lose.