Message center notification MC711019 covers the ability to hide the General channel for a team, a feature designed to free up space in the teams and channels list. Team members (including guests) can decide if they want to see the General channel in their list. Because teams can have up to 1,000 channels, being able to hide the General channel is a useful change.
SharePoint site owners can teamify (team-enable) their site, which is nice, Now you can create channel tabs based on site resources during the team enablement process. It’s a nice new feature but you must remember that a new team only has a General channel, so site resources will end up in a place where they might necessarily not end up in the long run.
Teams is removing system messages from the General channel in teams. System messages tell users about events like new members, but they’re really not that interesting, unless you’re fond of tracking the comings and goings of members, much like a noisy neighbor behind a curtain. Uncluttering the General channel is no reason to let it degrade, so keep it for important stuff and force conversations into other channels.