There has been reports of app hang with spinning color wheel. Turns out that the synchronous file read we implemented starting with version 2.2.4 is the root cause of the problem.
Now all file reads go back to asynchronous and will not block the UI thread. There is also a modification needed to avoid the UI thread from blocking, which requires sacrificing the panning speed of a zoomed image for macOS 10.13 and below.
Longer term, we plan to rewrite the display code to use Metal. This should improve the rendering speed with zooming and panning.
Finally, ExifTool has been updated to 11.30.