New router and effect of changing security setting from WPA to WPA2

I am planning on upgrading our LinkSys WRT54G2 to a new router, probably the Netgear Nighthawk AC R7000. When I do so, I plan to also upgrade our present WiFi security from WPA to the Nighthawk's default, WPA2-PSK (AES). I plan, however, to keep the old router's same SSID and password. I'm hoping all the client devices will immediately be able to sign on the the network, but is that the case?
Thank you for your help!
Gini

I've just had a Google around for you, check out this article: Clone Your Current Router for a Headache-Free Router Upgrade

Thank you for responding! I saw and read the same article when I Googled before turning to this board. In my case, though, I do plan to change the security protocol, and subsequently the Netgear forum users indicated that would require a new login for each device. I'd hoped to avoid that, but it's not really a big deal!

Yeah that's correct. You would need to sign each device back onto the network. But hey, once its done its done for another few years right?... :).