First you'll need to choose the UniFi equipment that meets the hardware and software requirements to replace your existing network

Next you'll need to configure it for cutover

Here are a few things to check for

Which VLANs exist on the current network? These will need to be recreated in UniFi under Settings > Networks.

Sometimes the router isn't the default gateway, the default gateway might be a web filter server for example. This could be different on each VLAN. This is configured in Settings > Networks > [Network].

The DNS servers might need to be set to a local Windows server or a specific external DNS provider. This could be different on each VLAN. This is configured in Settings > Networks > [Network].

It's common to leave some room in the DHCP scope for static IPs to be used. This can be configured in Settings > Networks > [Network] > Advanced > Manual > DHCP.

You'll want to make sure your new SSIDs and passwords match the the old network, otherwise every WiFi client will have to be updated to reconnect to the new network. This can be configured under Settings > WiFi. You should also check if the existing WiFi uses WPA2 or WPA 3 Enterprise with RADIUS authentication, or if the guest network uses a captive portal.

Remember to screenshot all the switch port configurations on the old network. You'll need to configure the UniFi switch ports to use the same VLAN configurations on the new switches. Sometimes it's easier to just plug everything in on the Default VLAN and then in UniFi look at which client is connected, then assign the VLAN for the port based on the client that is connected. But having a copy of the old port configuration can still be helpful.

Make sure you have the ISP settings configured for the UniFi router. If the WAN is not DHCP you'll need to configure the settings under Settings > Internet before adopting the UniFi router. We have a guides for setting up a UXG Lite/Max or a UXG Pro/Enterprise.

Check if the existing site is using a site-to-site VPN. This configuration will need to be recreated in UniFi under Settings > VPN > Site-to-Site VPN.

Check if the existing site has remote VPN users. These will need to be recreated under Settings > VPN > VPN Server.

Does the existing site have any port forward rules? If so, we recommend implementing a remote user VPN instead for better security. But if you have to recreate port forward rules it can be done under Settings > Routing > Port Forwarding.

Most firewalls block traffic between VLANs by default, but UniFi allows this by default. If you need to limit access between VLANs check our guides on how to block all inter VLAN traffic and then how to allow VLAN to VLAN traffic.