In a hybrid Exchange setup you are meant to leave the autodiscover record pointing at the onprem server. I have been going through DR planning and have realised that leaving it pointed onprem will cause disruption to clients in the event of loss of the on prem server.
My on prem server hosts no active mailboxes they are all now 365 so the server is only kept for attribute changes as AD accounts replicate using ADC.
My question is with the Hybrid setup in this state can the autodiscover record safely be pointed at 365?
If you do not have any mailboxes in on-premises, you can change the autodiscover to Office 365, you only need to change it back if you need to migrate mailboxes on-premises or use the autodiscover to use in Outlook and Mobile.