My original plan was that the 1.19 series firmware would be the last one for Duet 0.6 and 0.8.5, but I'll probably release 1.20 for the older Duets too. After that, releases will be minor ones to fix bugs only. The firmware for Duet WiFi and Duet Ethernet will change to being RTOS-based and the older Duets don't have enough RAM for that.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].