Unable to update to 0.9.37 of Grav core

Here is what I'm seeing when I do 'bin/gpm selfupgrade -f'

Grav v0.9.37 is now available [release date: Wed Aug 12 12:32:11 2015].
You are currently using v0.9.35.
Would you like to read the changelog before proceeding? [y|N] N
Would you like to upgrade now? [y|N] y

Preparing to upgrade to v0.9.37..
|- Downloading upgrade [2.15M]... 100%
|- Installing upgrade... Whoops\Exception\ErrorException: Class 'ZipArchive' not found in file /home/moggoly/public_html/system/src/Grav/Common/GPM/Installer.php on line 73
Stack trace:

1. () /home/moggoly/public_html/system/src/Grav/Common/GPM/Installer.php:73

This has previously worked fine, any ideas what the issue may be?

Ahhh, I've sorted this. Somehow the 'zip' PHP extension got disabled - can't work out how this occurred as I know I did an update to 0.9.35 only last week and didn't have any problems, and haven't touched the PHP settings.... Strange.

That's pretty odd. It was disabled in your php.ini file? If it was on a shared hosting environment, perhaps cpanel updated PHP and this value got reset?

Thats what I'm guessing happened, but I haven't the foggiest just what did it exactly. Oh well, I'll remember that for next time if I see that error.