PHP 7 compatibility extension for Magento 1 by Inchoo. Article with some tests and stats: http://inchoo.net/magento/its-alive/ .
Tested on M CE 1.9.2.2. Older versions of Magento may work, but may also have other problems, not fixed by this extension.
If you can, upgrade to 1.9.2.2 first. If you can't, this may be a good starting point to make a branch for older versions or EE.
Backwards compatible with PHP. Tested by us on PHP 5.6 & 5.5. Users have reported it working fine even on 5.3.3. Installing the extension before switching to PHP 7 is a good idea.
MIT. (See LICENSE.txt).
Yes. (Of course.) See Issues tab. Issue reporting is welcome. Pull requests are welcome.
For Composer install, available on Firegento: http://packages.firegento.com/ .
Or just download ZIP and copy files to appropriate locations.