Good morning, Im maintaining very old servers with Debian 7 which currently have ISPConfig 3.0.x. I'm performing updates on them to keep them online until I've moved all websites & emails into new Debian 9 servers. I'm asking if I can upgrade their ISPConfig to the latest version. Thank you for your help.
If you move them to new servers anyway, you better keep the old version. It might work, but I have not tested 3.1.13p1 on Debian 7.