cpanel 's EA, can we have older version?

Please be aware that eAccelerator is a third-party module; furthermore, cPanel EasyApache will use only the latest version of eAccelerator that works with the latest available PHP versions. Please note that the specified older release of eAccelerator, version 0.9.5.3, is not compatible with the latest PHP version 5.3.1.

To use an older version of eAccelerator it must be manually compiled; this is not a difficult task and may be accomplished by referencing the eAccelerator documentation: Install From Source - eAccelerator - Trac

For support using eAccelerator I recommend referring to the third-party vendor's official support channels, such as their official eAccelerator Users mailing list as referenced here: Mailing List - eAccelerator - Trac

 

From what I have seen in the past and to the best of my knowledge it will not remove or modify an existing custom extension; however, if the version of the extension is not compatible with selected PHP version then there will be inherent difficulty until the custom extension is upgraded. Using EasyApache Hook Scripts you could also have customizations backed-up prior to the build (e.g., preeasyapache) or other actions, including to compile and install any custom modules or extensions. Another option to have different versions is to use a custom option modules for EasyApache3 (as detailed in the documentation linked below).

Reference documentation:
EasyApache Hook Scripts
EasyApache Custom Modules