When I upgrade the mediawiki, I find the error message is happened in two computers.
These computers both using xcache and the version are 3.0.4 above, the only one computer upgrde successfully with 3.0.1 version xcache .
I don't sure if the version is the root cause.
But, according to some threads, that issue may relate with the cache setiing, I force edit the parameter in both LocalSettings of mediawiki.
$wgMainCacheType = 'xcache';
Copy the Code
The upgrading steps seems work fine, but I think it still should need to double check the procedure of forcing editing the cache type is correct or failed step.
