Thread:Project:Support desk/"CACHE ACCEL requested but no suitable object cache is present."/reply (3)

Make sure that XCache is installed with the new version of PHP. The most likely cause is the new version of PHP simply doesn't have xcache installed. You can do this by creating a php file with just the code  and then viewing it in a web browser.

Setting $wgMainCacheType = CACHE_NONE; will disable all caching, which would prevent the error, but make things slow.