The IOC 12.1 taxonomy was just released. It's a comparatively small one as far as splits and lumps go, with the majority in Asia and Australasia. See that list of changes on the IOC site.
This new taxonomy does include, for the first time, bird name translations in Serbian and Turkish; you can try these out from the Preferences page.
Scythebill now offers a "Restrained" sighting status - for birds you see in-hand, or in a mistnet, or similar circumstances. In North America, the American Birding Association's recording rules require that birds be unrestrained, and by default these sightings will not be considered "countable". But you can go to the Preferences page and make them countable if you wish.
If you mistyped a year, you might accidentally enter a checklist from the distant past or far future (the years "202" or "2202"). Scythebill will now warn you before proceeding when you enter these years on Enter Sightings.
The "Big day/year" report now properly supports "First sighting" reports. So you can go, year by year, and see which year (or even day) you had the most lifers.