As per https://gerrit.wikimedia.org/g/mediawiki/core/+/master/HISTORY, some methods are deprecated in MediaWiki core and should be removed from/replaced in extensions which still use them:
[X] ApiBase::dieUsageMsgOrDebug() - not found in any extensions in Gerrit as per 2018-10-01
[X] ApiBase::getErrorFromStatus() - not found in any extensions in Gerrit as per 2018-10-01
[ ] ApiBase::dieUsage() - replace with `ApiBase::dieWithError()` according to https://www.mediawiki.org/wiki/API/Architecture_work/i18n#MediaWiki_extension_changes
[ ] ApiBase::dieUsageMsg() - replace with `ApiBase::dieWithError` according to https://www.mediawiki.org/wiki/API/Architecture_work/i18n#MediaWiki_extension_changes
[x] ApiBase::parseMsg() - use can often be replaced with `dieWithError()` or `ApiMessage::create()` according to https://www.mediawiki.org/wiki/API/Architecture_work/i18n#MediaWiki_extension_changes
[x] ApiBase::setWarning() - replace with `ApiBase::addWarning()` according to https://www.mediawiki.org/wiki/API/Architecture_work/i18n#MediaWiki_extension_changes
Note: `ApiBase::dieWithError` was added in MediaWiki version 1.29 so the extension must require that MediaWiki version. If the file `extension.json` exists in that extension's code base, add the following lines (or increase the version when the existing version is lower):
```
"requires": {
"MediaWiki": ">= 1.29.0"
},
```