Yeaaaah, there were just 1 or 2 versions which had that bug that Update button was unavailable. To workaround it (if you're on that versions which is obviously you are) - go to the website and download from there:
Or you may request it from the support - they will send you the direct link.
Josh Lauderback
I'm currently running 25.5.6.5 and have been trying to update it seeing that there are multiple updates since then. No matter what I do, It is not allowing me to select the newest update (25.7.21.1). I have force closed EMU, restarted my MacBook and nothing has changed. Im currently running IOS 15.6. Any insight would be greatly appreciated!