PE values – adjusted vs historical

Q & APE values – adjusted vs historical
DAVID NG asked 5 years ago

Dear KC and Peter, I am looking through Shareinvestor’s website and I noticed that there are different PE values used. I hope you can explain what is the difference between : PE, rolling PE, PE (adjusted) and PE (historical). Which PE value should I focus on? Why is the PE value on the factsheet not the same as the adjusted PE value in the financial sheet? 
thanks