There is no need to notify Bisq about changes to an altcoin, since Bisq doesn’t incorporate any kind of an altcoin wallet.
If you are trying to notify users that are trading NavCoin on Bisq, I doubt there is much use of that either since NavCoin was last traded on Bisq about two years ago. In fact, there were only 6 trades that ever happened in Bisq regarding NavCoin.
I actually believe that there is a rule in Bisq that if a coin wasn’t traded in last few months, it should be removed, so it might not be around for very long.