Gtx combo firmware

[Stakan]

Hi. For many years I had a V8X where I choose to stay on original/stock firmware because of to many issues with Mars. This setup worked great until a thunderstorm destroyed the reciver.
Now I have a GtX Combo 8k and this is obviously with an old, stock version. Since Gtmedia has closed everything regarding recivers on their page I feel a bit lost in what to do since I feel the reciver seems a bit unstable.

1) What is the latest firmware update version? And where can I find this?
2) Is it possible to downgrade in a easy way if needed?