How do I autosplit my photos by date with new update?

You don't. Each import, even those events in the iPhoto library that was converted to the new Photos library, are placed in Moments based on the date taken. So some events that had multiple dates will be reduced to Moments, one moment for each date.

However, Moments in Photos are the new Events, i.e. groupings of photos sorted by date taken.

When the iPhoto Library was first migrated to Photos there was a folder created in the sidebar titled iPhoto Events and all migrated iPhoto Events (which are now Moments) are represented by an album in that folder. To open the sidebar if it's not already open use the Option+Command+S key combination.

There's a way to simulate events in Photos.

When new photos are imported into the Photos library go to the Last Import smart album, select all the photos and use the File ➙ New Album menu option or use the key combination Command+N. Name it as desired. It will appear just above the iPhoto Events folder where you can drag it into the iPhoto Events folder

When you click on the iPhoto Events folder you'll get a simulated iPhoto Events window.

The downside to the simulation is that the Albums/Events can only be sorted automatically by Title. But they can also be sorted manually, either in the sidebar or in the folder's window at the right.

Ask Apple for more sorting options in Photos via https://www.apple.com/feedback/photos.html.

look at moments in Photos - that is what is available - you can not change the split but it does split by time

LN