I searched for a solution for renaming multiple AP's at once while we build a network in a new building. I didn't find one so I hope how I did it might help someone else. Using postman I created the code needed to make the change to 1 ap's name. I exported that code to powershell. Then I took the part that is actually making the change and pasted it into the excel spreadsheet where I have my list of ap's and what their name should be. I used the concatenate function to insert the device serial numbers and names into that line of code. Then I pasted it all into powershell and clicked run. Here is what the code looked like with identifiable date changed. I am sure this method could be applied to make changes to other devices. I hope this helps someone.
$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$headers.Add("Accept", "*/*")
$headers.Add("Content-Type", "application/json")
$headers.Add("X-Cisco-Meraki-API-Key", "putapikeyhere")
$body = "{
`n `"name`": `"My AP`",
`n `"lat`": 37.4180951010362,
`n `"lng`": -122.098531723022,
`n `"serial`": `"Q000-ABCD-5678`",
`n `"mac`": `"00:00:00:33:44:55`",
`n `"tags`": `" recently-added `"
`n}"
$response = Invoke-RestMethod 'https://api.meraki.com/api/v0/networks/L_123456789123456789/devices/Q000-K5ZH-BFRX?name=A100' -Method 'PUT' -Headers $headers -Body $body
$response = Invoke-RestMethod 'https://api.meraki.com/api/v0/networks/L_123456789123456789/devices/Q000-6RP5-8WC6?name=A101' -Method 'PUT' -Headers $headers -Body $body
$response = Invoke-RestMethod 'https://api.meraki.com/api/v0/networks/L_123456789123456789/devices/Q000-AGNN-4B6D?name=A102' -Method 'PUT' -Headers $headers -Body $body
$response | ConvertTo-Json
