Manual:Extension support/1.17/ExtDowngrading

Namespaces
Since gendered namespace localizations were introduced in 1.18, many Language functions such as Language::getGenderNsText is no longer available. You will need to review your code and conditionally check if they exist before using them. A fallback for the previous is getNsText, but sometimes you may run into something that has no alternate. In that case you will have to conditionally drop functionality, or decide not to support older cores than 1.18.