Currently we do not support any legacy chips from any vendor. If you are a FPGA vendor and you want us to support any of your legacy chips, because supporting them in your current toolchain is a burden to you, please contact us. We would be happy to help.
Xilinx is no longer supporting its old design suite as it is focusing on its new Vivado design suite. But if you need to fix bugs in your old hardware designs like the Spartan3, you are stuck with a toolchain no longer supported by the toll vendor. The world moves on and your are left behind.
Within the next years, Xilinx ISE will probably no longer be installable on an up do date PC. So you will need to have an old PC around to support your Spartan 3-6 hardware.