Manual:$wgAutoloadAttemptLowercase/en

From Linux Web Expert

<translate> Extensions</translate>: $wgAutoloadAttemptLowercase
Switch controlling legacy case-insensitive classloading.
<translate> Introduced in version:</translate>1.23.0 (Gerrit change 92170; git #7f51cf22)
<translate> Deprecated in version:</translate>1.35.0 (Gerrit change 598739; git #2065d76b)
<translate> Removed in version:</translate>1.40.0 (Gerrit change 863722; git #8ae7194f)
<translate> Allowed values:</translate>(boolean)
<translate> Default value:</translate>false (1.35-1.39)
true (1.23-1.34)

Switch controlling legacy case-insensitive classloading. Default is to support case-insensitive loading. Do not disable if your wiki must support data created by PHP4, or by MediaWiki 1.4 or earlier.