Dharma, Below is a post I saved from Michael Catrambone. I think this is what you are looking for. I haven't tried it myself, I still just have 15.5.1 loaded. Good luck Gary E. MacIndoe PCB Design Engineer Fort Collins, Colorado amd.com gary.macindoe@xxxxxxx -----Original Message----- From: icu-pcb-forum-bounce@xxxxxxxxxxxxx [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Michael Catrambone Sent: Thursday, November 15, 2007 12:07 PM To: icu-pcb-forum@xxxxxxxxxxxxx Subject: [PCB_FORUM] Re: Switching between two versions of Allegro PCB Importance: High Hey Gary, I have had great success using the Cadence Switch Release executable which has been part of the standard Cadence install for some time now <Install Dir>\tools\bin\switchversion.exe). This will list all the Allegro releases at the time of installation and you simply select the release and click OK. I have 15.5.1, 15.7 and 16.0 loaded on the same PC and I execute the Cadence Switch Release executable from the last loaded release and select the lower version you would like to run. The only thing that I have to worry about is the location of the PCBENV directory for each of the releases which can be easily controlled by re-targeting your HOME directory to a different location. New to SPB 16.0, is a new Windows environmental variable (ALLEGRO_PCBENV) that gives the ability to re-target your PCBENV directory to a different location without having to change you HOME directory. Hope this helps, Michael Catrambone UTStarcom, Inc. -----Original Message----- ________________________________ From: icu-pcb-forum-bounce@xxxxxxxxxxxxx [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Dharma Kemp-Bresett Sent: Wednesday, January 09, 2008 10:20 AM To: icu-pcb-forum@xxxxxxxxxxxxx Subject: [PCB_FORUM] Has anyone been able to "backrev" from version 16.0 to version 15.7? Hi Everyone, I thought I had seen somewhere that it was possible to take a board done in 16.0 back to 15.7 but now I am not finding any info on that...has anyone been able to accomplish this? Thanks in advance, Dharma KAW/USA Ltd. 39 Simon Street, #4 Nashua, NH 03060 603-886-8711 x212 603-881-8763 fax Confidentiality Notice: This email and any accompanying documents contain information that is confidential, privileged or exempt from disclosure under applicable law and is intended for the exclusive use of the addressee. This information is private and protected by law. If you are not the intended recipient, or have received this email in error, you are hereby notified that any disclosure, copying, distribution or use of the contents of this document in any manner is strictly prohibited.