This feature is not included in the buddypress standard installation.
If you are using a plugin, than go to the plugin group of the site and ask for support over there.
Sorry, but I dont think that a plugin is responsible for this option, I do not remember a plugin that sends group updates by mail. That must be a feature of Buddypress…
This is the default behaviour, which is kind of counter-intuitive.
I would recommend using the BP Group Email subscription plugin instead (which I believe you’re thinking of):
https://wordpress.org/extend/plugins/buddypress-group-email-subscription/
Thank you r-a-y for the link to the plugin. It is very great, but this has still nothing to do with my request. On the main Admin Site of each group I have the tab “Change details” where I can set the group name and description. Below this I have “Inform members about changes by E-Mail”, which I can set to Yes or No. But when I set it to Yes, it automaticalls goes back to No.
Like I mentioned, that is the intended behaviour. This is probably done to prevent accidentally spamming your users every time the group description is changed.
File a ticket if you are not satisfied with this:
https://trac.buddypress.org/newticket
Login with the same credentials you use here on bp.org.
I would say it is very deliberate intended behavior – imagine: you don’t really want to necessarily inform members of every single change, you choose when it’s appropriate to do so rather than have the system do it automatically for any adjustment you may make that is of little interest to members.
It possibly should be better labeled along the lines of ‘Inform members of *this* change’ and a checkbox rather than radio buttons
