@Chapelhill_IT although it is already mentioned in the article @RWelch has shared above, the overall idea is as follows: - Carefully move all the vlans and their gateway IPs (except the MS management one) to the MS425  - As you are moving these VLANs - ensure correct static route on the MX as well pointing towards the MS425 for the correct subnets. - Once you MS switch is capable of handling most of the VLANs - only have one transit VLAN between the MX and the MS425. You can either do this via access port or trunk port with pruned VLANs. Also, ensure a static default route on the L3 MS towards the MX.  - Ensure that the management interface and transit VLAN SVI of the MS425 are two different IPs and management interface points to MX as its gateway.     Although, I have seen some scenarios where the customers are using more than just 1 transit VLAN between MX and Layer 3 MS - and it does work but not considered as best practice.  If you get into any complications when performing this task, just reach out to Meraki support via https://meraki.cisco.com/support/  ... View more