While at the recent MUM in Dallas i thought I heard understood that it was now possible to remotely scan from a wireless client without losing connection to the AP.
This is useful for remote scanning to make sure the installer connected them to the AP with the best signal after the installer has left the customers location.  This is possible with most of our other vendors products.  Does anyone know if this is possible from mikrotik wireless client.  From the local side it is no problem but this requires being on location.  Any help would be much appreciated.

Yes, I can confirm that, it works. Just tested with 6.35.4 with wireless-rep. During the background scand the sustained 3M/3M traffic of the client was not interrupted, scan was done in winbox connected over the wlan which was used for scanning.

I have setup as you suggested and get error saying "Couldn't start - background scan not supported in the state (6)"
Is the feature not available for 5GHz A/N ?  Is this only available in 5AC ??

I did the test on old rb411 with 5g a only card. 6.35.4, wireless rep package, client bridge mode.

Did some testing and found the issue i was having is the AP and clients were running nstreme which is the reason for the error in my above post.  Changed to 802.11 and background scan works.
Thanks

For now, this function is only available for, Wirelles Protocol 802.11, I hope that Mikrotik will develop soon to NV2