Why no virtual destructors?

My C++ is quite rusty after more than 30 years not using that language. But I remember to always define destructors as virtual when the class has other virtual methods (I’ve been bitten by these memory leaks when not doing so, a long time ago…). This article gives good explanations when to do so. So I was surprised to see that the destructors are not declared virtual in the plugin C++ header template files and plugin examples.
For instance: SDK/Templates/genericChatSubscriber.h · master · savoirfairelinux / jami-plugins · GitLab or SDK/Templates/genericMediaSubscriber.h · master · savoirfairelinux / jami-plugins · GitLab

Is it a potential bug or are there reasons I don’t catch and I should still update my C++?

You don’t need to define virtual destructor for every class that inherits. Only the base class needs to define virtual destructor if i’m not mistaken.