I was preparing to update from 17.2.31 to the latest stable release. I clicked the "Download" button while making my preparations. The button did not say "download and install". There was no indication that installation would proceed automatically, nor that the server on which the software resides would automatically reboot.
I sincerely hope this issue is resolved in future versions, but if not: I'd consider this a bug. I was not done with my preparations and the server automatically proceeded without my interaction.