This is private revelation, not a Church doctrine that we are required to believe. (View segment from 0:00 to 3:40. You’ll need to read the text on the screen.)
What souls are at the lowest level of Purgatory?
Those who were barely saved and had committed terrible crimes.
Souls who were indifferent towards God.
People in the religious life who were lukewarm or neglectful of their duties.
What is the final stage of Purgatory?
The Threshold.
Souls there are being purified of not loving God enough.
Did this video help you to realize the importance of loving God and others as best you can right now?