Upgrade firmware for a BH20?

I know this is a long shot given the age of the equipment and the EOL status. We are planning on replacing this link in the near future anyway.

We have an old BH20 P10 (DES) link in use for a (now not-so) small business that is running 8.2.7. Is there newer firmware we can load on this unit? I know they are related to PTP100 series radios, but I don’t know if they are close enough to load newer firmware like 13.4.1 or even 11.1.

Would it be safe to push PTP100 firmware onto these radios?
If so would they handle 13.4.1?
If they cannot use the PTP 100 firmware, does anyone know or have the correct firmware for the radios?

As stated before, we are planning on phasing out this link. We have had a lot of issues with radar avoidance in the 5.4/5.6 bands and are trying to help them “limp along” until we can either replace them with newer radios or get fiber to their door. I seem to remember one of the later firmware versions helping with the time length when they do jump channels, or making them slightly less reactive to minor interference vs actual radar activity. Any help at all would be appreciated.