In Automatic 1.x, there was an option called “Download every episode once”. If enabled, it would make sure that each episode in a series of episodic content would be downloaded only once, regardless of how many times it (re)appeared in the feed.
There was a catch, however: it only worked if the subscription was set up to match a single series. If the subscription was matching multiple series, and the episode numbers overlapped, there were false negatives. This was a one of the most common issues users had with subscriptions.
With 2.0, this feature can still be found for Custom subscriptions under the name “Try to download every episode once”. But it’s been upgraded to be a little smarter: it can now differentiate between episode numbers that belong to different series. So if a Custom subscription is grabbing multiple series, this option can now safely be enabled.
As an aside, the “Unless tagged as ‘proper’ or ‘repack’” option has been removed, and these tags are now universally respected for all subscriptions.