Saudi Exit Re-entry Date

The re-entry date shows:
Return Before (Gregorian): Dec. 31, 2016
My question for clarification:
Does it mean I can enter Saudi Arabia before the start of Dec. 31 (mid night Dec. 30) or I can enter before the start of January First.
Thank you.

31 December full day is permissible to enter. However I never took chance like that to be on the brink. Any flight problem will create problem

Thank you so much.

Sir my exit re entry visa returun 11/6/2021 i enter saudi arabiya 11 or 10mid night please confirm or returun11midnight please confirm