IANAL, but the new license applies only to new PHP versions, changing it backwards would require approvals.
If you don't contribute under new license, you should be not affected.
The new license covers and applies to all the code, even code that was written before the change.
You can totally change the license of already released code, if the change is compatible with the precious license or if you have permission from all the contributors whose code is still present in significant amount. (However, you can't prevent people from using the released code under the former license)
I believe only the rights holders need to approve of the retroactive changes, and so they really only need Perforce (presumably the rights holder as the current owner of the former Zend Technologies) to agree.
Very pedantically, because PHP doesn't require copyright assignment, it would be (almost certainly) impossible to retroactively change the licence on older versions.
However, since the PHP and Zend licences both permit the user to use PHP under the terms of whatever licence version was applied to that PHP version or any later version, the point is essentially moot, since a user can choose to use the new version of the PHP/Zend licence once published, which will give them the same rights.
jraph|7 months ago
You can totally change the license of already released code, if the change is compatible with the precious license or if you have permission from all the contributors whose code is still present in significant amount. (However, you can't prevent people from using the released code under the former license)
sjs382|7 months ago
zdragnar|7 months ago
LawnGnome|7 months ago
However, since the PHP and Zend licences both permit the user to use PHP under the terms of whatever licence version was applied to that PHP version or any later version, the point is essentially moot, since a user can choose to use the new version of the PHP/Zend licence once published, which will give them the same rights.