The Brush panel in earlier releases of Photoshop is now called Brush Settings.
The Brush Presets panel in earlier versions of Photoshop has been streamlined and renamed as Brushes panel. For more information, see Streamlined brush preset management.
Device Preview is no longer available in this release. Additionally, the Preview CC iOS app is no longer available for download or actively maintained as of October 2017. If you have a previously-downloaded version of Preview CC on your iOS device, you can continue to use it on an as-is basis with earlier versions of Photoshop.
Photoshop no longer prompts you to import assets into Creative Cloud Libraries while opening documents. You can still automatically import all assets from an open document using the Create New Library From Document command in the Libraries panel.
The Preferences > General > Show Recent Files Workspace When Opening A File setting is no longer available.
On macOS 10.13 (High Sierra) and newer, Photoshop uses a dark title bar for floating document windows when UI brightness is set to one of the two dark settings.
The Enable History Scrubbing In The Touch Bar preference is no longer available. To suppress history scrubbing, simply remove the corresponding button from the Touch Bar layout.
You can now control brush smoothing using the Touch Bar. Add this control to the Touch Bar using the Customize Touch Bar user interface.
PNG files created using the Save As option are now compressed better. Also, the options for saving images as PNG assets have changed for better user experience: