For a web browser, that's certainly getting into dangerous territory. You want your web browser to be updated as rapidly as possible; zero days are a fact of life.
There are some apps for which I would agree, but not when it comes to web browsers. And my apologies, Gab's Dissenter hasn't been updated since v1.5.114, which was released back in March of 2020. So their last major build for Windows and Linux is nearing a year without an update. Their macOS build (0.70.122) is from November of 2019.
Software does not, and perhaps I should say should not, need to constantly change.
This is completely orthogonal to Gab's political leaning.