Hi all: I recently upgraded our wiki from 1.8.2 to 1.15.1 and, since the upgrade, the site has been white-screening at various times. Our hosting provider suggested this morning that there may be a compatibility bug between the new site code and APC. He said that PHP scripts were being called, but were not generating any output. He restarted Apache and, since then, pages seem to be loading normally. So, this made me curious about what PHP accelerator is recommended / used by MediaWiki.org -- eAccelerator, mmTurck, or APC? An article on MediaWiki.org says that, "[d]epending on the cache and options used, you may have to perform a special operation whenever updating script files." Can someone tell me what "special operation" means? For more information, please see the following article / section on MediaWiki.org: http://www.mediawiki.org/wiki/PHP_configuration#Opcode_caching Also, in order for APC to work correctly, does $wgMainCacheType need to be set to "CACHE_ACCEL"? Thanks in advance for any advice you can give me on this, Patricia Barden