In regards to the very first post. Not sure if it's already been said. Just skimming through. But chances are, as I've seen people say, no and never

Im sure in maybe 20 years something will change within that time. But yeah. Not anytime soon I would say.
Also with majority of people using lower line speeds if upgraded, as some have said, would be more stress on everything.
And with higher speeds, it's alot easier to burn bandwidth. So... telkom of course wont want that. Sooo.... all in all. I doubt we'll get upgraded anytime soon. Maybe when we're all dead and our children's children's children!!! are alive. They'll upgrade :3
On the bright side though telkom did upgrade I think it was 2GB users was it? and up to a higher cap limit which is quite nice. I now have 9GB. Sure it's small compared to overseas with their 200+GB caps and uncapped lol. But hey. It's better than nothing.
So least I got one prayer answered ^^
And in regards to the line speed increase only being x amount more. Regardless. Not everybody's line can support 4mbit anyways due to the whole quality of line, being however far away you are from the exchange. And these days prices for EVREYTHING are going up. So it can be as little as possible. But it's still more which means less money for food, paying your water etc. Already I've known at least 5 families of friends that have been having issues with money. So meh. Couldn't care about the price difference. But lets not go on about that
A slight speed increase would be nice. But Im sure it will be upgraded. Just not anytime soon. So to answer the question in a quick post.
No known date. Nothing has been said. It wont be anytime soon going by how telkom is going about things. So we can count on NOT being upgraded anytime soon. I think it would be safe to say not even within a year. (Again Im going by how telkom is going about things)