It means your current NWJS (browser) profile is newer than the version of NWJS you are currently using. The profile contains stuff like cookies, settings and other things. I mean... its literally Chromium. I'm not sure what you are doing so I can't really offer any suggestions.
Well, I reported the issue in the appropriate Discord channel. My single message got flagged immediately. One of their mods DMed me and started accusing me of being a pirate. I had a nice chat with him actually but he decided to server ban me for basically helping people.
Dear NLT mod, I know you are watching this thread. Being hostile to potential supporters will likely have the opposite effect.
In other news... transcoding is about 80% done. I tried a few videos in-game and they seem to work fine. Interestingly, VP9 seems to compress 60-80% better than H.264 does.