I'm looking forward to Thunderbird 102 with its new features. However I would like to install and run it separately from my existing TB 91.9.0, essentially so as to treat version 102 as a beta and so that I can roll back to version 91.9.0 if I'm not happy with 102 and so that the revamped features such as the new address book will not cause irreversible change. Is there any information online to help with this, or does anyone have any advice? Thank you Andy