when adding series to TMDB is the parameter of the THeTVDB ID relevant to do the migration to TMDB in the SeriesGuide app? I have not found any information about this.
Or is it relevant that there are the same of amount or more episodes?
As far as I know : if you add thetvdb show number in themoviedb, trakt can make the link between the shows. And then seriesguide knows what seasons and episodes you watched in thetvdb, and if they exist in themoviedb, it marks them in the data from themoviedb as read there too.
It looks like a lot of people are trying their best to update series on themoviedb. I myself have added all series I watched that were missing according to trakt. Now waiting to find out what series are missing episodes. I find the comparison lists on trakt, but they need updating. Don’t know when they do that, maybe once a week?