Manual:$wgCheckSerialized

Cache: $wgCheckSerialized
Check if serialised files are up to date.
Introduced in version:1.12.0 (r27983)
Removed in version:1.16.0
Allowed values:(boolean)
Default value:true

Details edit

Set to false if you are thorough system admin who always remembers to keep serialized files up to date to save few mtime calls.