As part of the project requirements i need to install mirroring, so that changes can be pushed from an editing environment to the live environment - however you can only install mirroring on a 7.5 instance - does anyone know how to achieve this? Our site is in the final stages of development so rolling back to 7.5 is not an option.
Have a look at this answer: http://world.episerver.com/forum/developer-forum/-Episerver-75-CMS/Thread-Container/2016/5/episerver-cms-9-mirroring/
Worth mentioning is that I think mirroring is about to go away. Not sure but if i remember correct they talked about moving into some other technology. Not sure though.
Don't the hints from documentation not work? http://world.episerver.com/documentation/developer-guides/CMS/Deployment/mirroring2/