Can not force 5GHz Wifi connection speed on Nexus6 running Android 7 hsa disappeared Android 7

[AC Question]

Recently noticed that the ability to explicitly select your Wifi Connection Speed has disappeared from the Nexus 6 Android 7 (Any build). i.e. I am no longer able to select and force 5GHz connection speed for WiFi. This was possible in the past.
Does any one know when this disappeared and with which version and build of Android?

 

[anon(632115)]

Use 2 ssids, one for 5ghz and log in to that one