Now that Apple no longer sells Time Capsule, what would be the best way to update my backup/router system? I have a version 7.8.1.1T TCapsule and a vision 7.8.1, 4ish year old airport express. Thanks for any input in advance.

Got a notification that my Time Capsule hadn't backed up iMac for more than a week. Reselected wi fi system and it's up and running. But now that Apple no longer sells the Time Capsule, what would be the best way to update my backup/router system? I have a Model 1355, version 7.8.1. 1TByte TCapsule and a version 7.8.1, 4ish year old airport express. I've been very pleased w the Time Capsule, Aiport Express setup, but I know things change. Thanks for any input in advance.