I doubt there will ever be an official WhatsApp group, we already have the forums and a Discord server as well. WhatsApp would just be a duplicate to the role Discord already fills and does better at the same time.
We also don't really focus on Discord as although it has good features it is lacking in a few ways. It isn't searchable via search engines which is a powerful tool for discovery for all users new and old, it isn't totally under TGCs control, what do we do if Discord fades away in a few years and all the years of community contribution are lost. Also ever person has a web browser (and can access the forums) not everyone has discord knows what it is or wants to download another app.
I have yet to have seen anything that can reliably replace the role of a good forum, there may be improvements that could be made to the TGC forum but it has worked well for years and is a wonderful reliable resource.
Discord is meant to fill that chat room role the old AOL system is definitely dead now
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