The short answer
Yes. Rebuilt or re-downloaded automatically when needed.
What is it?
Firmware files (.ipsw) that Finder downloads when you update or restore an iPhone from your Mac, kept in ~/Library/iTunes/iPhone Software Updates. Each is several GB, and only the latest one is ever useful.
What happens if you delete it?
Finder downloads a current firmware file from Apple the next time you update or restore the iPhone. Nothing on the device or in your backups depends on these files.
How to remove it properly
Move ~/Library/iTunes/iPhone Software Updates (or the .ipsw files inside it) to the Trash in Finder with Go › Go to Folder….
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
How MoreRoom helps
MoreRoom recognises this item, shows its real size and when it was last used, and labels it “Safe to remove”. In the free version you can move it to the Trash in one click, with Undo; Pro collects every safe item at once.
Frequently asked questions
Is it safe to delete iPhone Software Updates (IPSW) on Mac?
Yes. Rebuilt or re-downloaded automatically when needed. Finder downloads a current firmware file from Apple the next time you update or restore the iPhone. Nothing on the device or in your backups depends on these files.
Will iOS software updates (IPSW) come back after I delete it?
Yes. Finder downloads a current firmware file from Apple the next time you update or restore the iPhone. Nothing on the device or in your backups depends on these files.
How do I remove iOS software updates (IPSW) properly?
Move ~/Library/iTunes/iPhone Software Updates (or the .ipsw files inside it) to the Trash in Finder with Go › Go to Folder….