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So I heard there is a chance this story never gets finished because the novel writer is barely updating and at its current pace will never get finished.

The author is Mad Snail. He is known to start new Light Novels and leave the previous ones half finished.
Same with Tales of Demons and Gods, he is writing only 1 chapter (if you can call 250-300 words a chapter, it is barely an essay) per MONTH for the last 4 years on this story. It became so sad that at this point even he himself forgot his own story and started to make important mistakes, plot holes, repeats..

For the Donghua it is not yet known if we will get a 5th season or not.
Currently the end of Season 4's last episode is adapted from Chapter 150-152 from the Light Novel and Light Novel has a total of 496 chapters so far. (Even though the last 100 or so chapters are much shorter then the earlier ones) So there should be at least another 8-9 seasons (300-350 episodes) on the Donghua to catch up to the Light Novel.

In order to finish the Light Novel it probably needs around another 300-350 chapters. But at this speed of release (1 chapter/Month) that will take around 30 YEARS..
Such a shame, one of my and many other people's favorite anime (donghua) / Light Novel and it is left to die.
He could easily release 10-12 episodes a week (that's around 3000 words, "I Shall Seal the Heavens" author were releasing 4-5 times more then that every week) if he wanted to and finish the story in half a year, but apparently it won't happen. He is probably only trying to fill the minimum requirement of his contract, before entirely dropping the story.