How to Fix the “Incompatible File Format” Error on Zend-Encrypted PHP Pages
I have a PHP program that uses Zend encryption. When deploying it on a hosting server, I encountered the following error: Fatal error: Incompatible file format: The encoded file has format major ID 3, whereas the Loader expects 4 in
After summarizing findings from Baidu, here is the relevant information about this issue:
- Starting from PHP 5.3, to support PHP code encrypted by Zend Guard, you must install Zend Guard Loader. The old Zend Optimizer is no longer supported.
- Zend-encrypted programs created for versions before PHP 5.2 are parsed by Zend Optimizer.
- Zend-encrypted programs starting from PHP 5.3 are parsed by Zend Guard Loader.
In summary, the cause of this problem is that Zend Guard 5.1 updated the algorithm for encrypting PHP files to comply with PHP 5.3. PHP files encrypted with older versions of Zend Guard cannot run properly under a PHP 5.3 + Zend Guard Loader environment and will throw the error mentioned at the beginning of this article.
Solutions:
- Re-encrypt the PHP source files under Zend Guard 5.1, after which they can be viewed. Since I only have the encrypted commercial code, this option is not feasible.
- Alternatively, move the application to a PHP 5.2 + Zend Optimizer environment to run it. I chose this approach to run this encrypted application.
I migrated the hosting space to an environment with a lower PHP version, and it worked. The before-and-after PHP environments are as follows:
- Before migration: PHP 5.3.17 + Zend Engine v2.3.0 + Zend Guard Loader v3.3
- After migration: PHP 5.2.17 + Zend Engine v2.2.0 + Zend Optimizer v3.3.9