I assume that you simply removed power from the SONOS units as you packed them away. In your new apartment you’ll have a different router/Gateway.
During the initial setup in your new apartment, apply power to all of the SONOS units and wire the soundbar to your router. If you ultimately plan to use WiFi connect SONOS, this wired setup will be temporary. I expect that the old SONOS controllers will find the system. The controller may demand a SONOS system update. If there is a discussion about “upgrading” to S2, pause and get back to us because there are some considerations that we should discuss, otherwise approve the update. If we need to discuss this, please give us the router and SONOS model numbers. Refrain from any SONOS Factory Reset without further consult.
Once you get the SONOS system online, go to Settings → System → Network → Manage Networks and update your WiFi settings. Unless you have a MOVE or ROAM, you don’t need to define a WiFi network as long as you keep the soundbar wired to the network.