We have removed #RSSGuard from our list of recommended software.
Its JavaScript article filters are the USP for RSS Guard, because they're so much more powerful than the filtering by search words or regular expressions available in other feed reader applications.
Migration from 4.8.6 to version 5 is only mostly seamless for local accounts. Still, you lose your assignments of article filters to the specific RSS feeds you want them applied to.
Users of Nextcloud News are losing their article filters, completely.